diff --git a/front/src/app/api/admin/check-permission/route.ts b/front/src/app/api/admin/check-permission/route.ts
new file mode 100644
index 0000000..d9c5550
--- /dev/null
+++ b/front/src/app/api/admin/check-permission/route.ts
@@ -0,0 +1,26 @@
+import { NextRequest, NextResponse } from "next/server";
+import { auth } from "@/lib/auth/auth";
+import { checkAdminPermission } from "@/lib/api/checkAdminPermission";
+
+export async function GET(request: NextRequest) {
+  try {
+    const session = await auth();
+    if (!session?.user?.email) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+    }
+
+    const { searchParams } = new URL(request.url);
+    const roomId = searchParams.get("roomId");
+
+    if (!roomId) {
+      return NextResponse.json({ error: "roomId is required" }, { status: 400 });
+    }
+
+    const isAdmin = await checkAdminPermission(session.user.email, roomId);
+    
+    return NextResponse.json({ isAdmin });
+  } catch (error) {
+    console.error("Error checking admin permission:", error);
+    return NextResponse.json({ error: "Internal server error" }, { status: 500 });
+  }
+}
\ No newline at end of file
diff --git a/front/src/app/room/[roomId]/page.tsx b/front/src/app/room/[roomId]/page.tsx
index ca1ecc4..e95f967 100644
--- a/front/src/app/room/[roomId]/page.tsx
+++ b/front/src/app/room/[roomId]/page.tsx
@@ -45,10 +45,12 @@ export default async function RoomPage({
     }
 
     return (
-      <ClosedEventTemplate
-        userIcons={userIcons}
-        imgUrl={event.imageUrl}
-      />
+      <SessionProvider>
+        <ClosedEventTemplate
+          userIcons={userIcons}
+          imgUrl={event.imageUrl}
+        />
+      </SessionProvider>
     )
   }
 
@@ -60,6 +62,7 @@ export default async function RoomPage({
     const res = await selectUserByEmail(user.email);
 
     if (res) {
+      user.id = res.id.toString();
       user.name = res.name;
       user.bio = res.bio ?? "";
       user.interests = res.interests ?? "";
@@ -72,6 +75,7 @@ export default async function RoomPage({
       user.name = "New User";
 
       const userId = await insertNewUser(user.email);
+      user.id = userId.toString();
       await insertMemberAssignment(userId, event.userGroupId);
     }
   }
diff --git a/front/src/components/organisms/room/DeleteConfirmDialog.tsx b/front/src/components/organisms/room/DeleteConfirmDialog.tsx
new file mode 100644
index 0000000..02c4961
--- /dev/null
+++ b/front/src/components/organisms/room/DeleteConfirmDialog.tsx
@@ -0,0 +1,63 @@
+"use client";
+
+import { useState } from "react";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/atoms/shadcn/dialog";
+import { Button } from "@/components/atoms/shadcn/button";
+
+interface DeleteConfirmDialogProps {
+  isOpen: boolean;
+  onClose: () => void;
+  onConfirm: () => void;
+  userName: string;
+}
+
+export default function DeleteConfirmDialog({
+  isOpen,
+  onClose,
+  onConfirm,
+  userName,
+}: DeleteConfirmDialogProps) {
+  const [isDeleting, setIsDeleting] = useState(false);
+
+  const handleConfirm = async () => {
+    setIsDeleting(true);
+    try {
+      await onConfirm();
+    } finally {
+      setIsDeleting(false);
+      onClose();
+    }
+  };
+
+  return (
+    <Dialog open={isOpen} onOpenChange={onClose}>
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>ユーザーを削除しますか？</DialogTitle>
+          <DialogDescription>
+            「{userName}」をルームから削除します。この操作は取り消せません。
+          </DialogDescription>
+        </DialogHeader>
+        <DialogFooter>
+          <Button variant="outline" onClick={onClose} disabled={isDeleting}>
+            キャンセル
+          </Button>
+          <Button
+            variant="destructive"
+            onClick={handleConfirm}
+            disabled={isDeleting}
+          >
+            {isDeleting ? "削除中..." : "削除"}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}
\ No newline at end of file
diff --git a/front/src/components/organisms/room/NonDraggableIcon.tsx b/front/src/components/organisms/room/NonDraggableIcon.tsx
index 9c36279..f1cad07 100644
--- a/front/src/components/organisms/room/NonDraggableIcon.tsx
+++ b/front/src/components/organisms/room/NonDraggableIcon.tsx
@@ -1,3 +1,7 @@
+"use client";
+
+import { useState, useEffect } from "react";
+import { useSession } from "next-auth/react";
 import {
   Avatar,
   AvatarFallback,
@@ -6,32 +10,88 @@ import {
 import { User } from "lucide-react";
 import { UserIcon } from "@/types/room/shared";
 import UserIconTooltip from "./UserIconTooltip";
+import DeleteConfirmDialog from "./DeleteConfirmDialog";
+import { deleteUserFromRoom } from "@/lib/api/deleteUser";
 
 export default function NonDraggableIcon({
-  icon 
+  icon,
+  roomId
 } : {
-  icon: UserIcon
+  icon: UserIcon,
+  roomId?: string
 }) {
+  const { data: session } = useSession();
+  const [showDeleteDialog, setShowDeleteDialog] = useState(false);
+  const [isAdmin, setIsAdmin] = useState(false);
+  
+  // roomIdがない場合（終了したイベント）は削除機能を無効化
+  const canDelete = roomId && isAdmin;
+
+  useEffect(() => {
+    const checkAdmin = async () => {
+      if (session?.user?.email && roomId) {
+        try {
+          const response = await fetch(`/api/admin/check-permission?roomId=${roomId}`);
+          if (response.ok) {
+            const data = await response.json();
+            setIsAdmin(data.isAdmin);
+          }
+        } catch (error) {
+          console.error("Failed to check admin permission:", error);
+          setIsAdmin(false);
+        }
+      }
+    };
+    
+    checkAdmin();
+  }, [session?.user?.email, roomId]);
+
+  const handleClick = (e: React.MouseEvent) => {
+    e.preventDefault();
+    if (canDelete) {
+      setShowDeleteDialog(true);
+    }
+  };
+
+  const handleDeleteConfirm = async () => {
+    if (!roomId) return;
+    try {
+      await deleteUserFromRoom(roomId, icon.user.id);
+    } catch (error) {
+      console.error("Failed to delete user:", error);
+    }
+  };
 
   return (
-    <div
-      className="absolute size-12"
-      style={{transform: `translate(${icon.position.x}px, ${icon.position.y}px)`}}
-    >
-      <UserIconTooltip user={icon.user}>
-        <Avatar
-          className="size-12"
-          onClick={(e) => e.preventDefault()}
-          onPointerDown={(e) => e.preventDefault()}
-        >
-          <AvatarImage 
-            src={`${icon.user.image}`}
-            draggable="false"
-            referrerPolicy="no-referrer"
-          />
-          <AvatarFallback><User /></AvatarFallback> 
-        </Avatar>
-      </UserIconTooltip>
-    </div>
+    <>
+      <div
+        className="absolute size-12"
+        style={{transform: `translate(${icon.position.x}px, ${icon.position.y}px)`}}
+      >
+        <UserIconTooltip user={icon.user}>
+          <Avatar
+            className={`size-12 ${canDelete ? 'cursor-pointer hover:opacity-80' : ''}`}
+            onClick={handleClick}
+            onPointerDown={(e) => e.preventDefault()}
+          >
+            <AvatarImage 
+              src={`${icon.user.image}`}
+              draggable="false"
+              referrerPolicy="no-referrer"
+            />
+            <AvatarFallback><User /></AvatarFallback> 
+          </Avatar>
+        </UserIconTooltip>
+      </div>
+      
+      {canDelete && (
+        <DeleteConfirmDialog
+          isOpen={showDeleteDialog}
+          onClose={() => setShowDeleteDialog(false)}
+          onConfirm={handleDeleteConfirm}
+          userName={icon.user.name || "Unknown User"}
+        />
+      )}
+    </>
   )
 }
diff --git a/front/src/components/templates/room/ActiveEventTemplate.tsx b/front/src/components/templates/room/ActiveEventTemplate.tsx
index 15f0c77..d44ba2e 100644
--- a/front/src/components/templates/room/ActiveEventTemplate.tsx
+++ b/front/src/components/templates/room/ActiveEventTemplate.tsx
@@ -82,7 +82,7 @@ export default function ActiveEventTemplate({
       {imgUrl && <VenueImage imgUrl={imgUrl}/>}
       {userIcons.map((icon, i) => {
         if (icon.user.id !== userId) {
-          return <NonDraggableIcon key={i} icon={icon}/>
+          return <NonDraggableIcon key={i} icon={icon} roomId={roomId}/>
         } else {
           return <DraggableIcon key={i} socket={socket} icon={icon} scale={scale}/>
         }
diff --git a/front/src/lib/api/checkAdminPermission.ts b/front/src/lib/api/checkAdminPermission.ts
new file mode 100644
index 0000000..0bb08c0
--- /dev/null
+++ b/front/src/lib/api/checkAdminPermission.ts
@@ -0,0 +1,21 @@
+import { selectEventById } from "@/lib/db/event";
+import { isUserAdminOfGroup } from "@/lib/db/user_group_assignment";
+import { selectUserByEmail } from "@/lib/db/user";
+
+export async function checkAdminPermission(userEmail: string, roomId: string): Promise<boolean> {
+  try {
+    const eventId = Number(roomId);
+    if (isNaN(eventId)) return false;
+
+    const event = await selectEventById(eventId);
+    if (!event) return false;
+
+    const user = await selectUserByEmail(userEmail);
+    if (!user) return false;
+
+    return await isUserAdminOfGroup(user.id, event.userGroupId);
+  } catch (error) {
+    console.error("Failed to check admin permission:", error);
+    return false;
+  }
+}
\ No newline at end of file
diff --git a/front/src/lib/api/deleteUser.ts b/front/src/lib/api/deleteUser.ts
new file mode 100644
index 0000000..797e8bd
--- /dev/null
+++ b/front/src/lib/api/deleteUser.ts
@@ -0,0 +1,15 @@
+import { PARTYKIT_URL } from "@/app/env";
+
+export async function deleteUserFromRoom(roomId: string, userId: string): Promise<void> {
+  const response = await fetch(`${PARTYKIT_URL}/parties/main/${roomId}`, {
+    method: "DELETE",
+    body: JSON.stringify(userId),
+    headers: {
+      "Content-Type": "application/json",
+    },
+  });
+
+  if (!response.ok) {
+    throw new Error(`Failed to delete user: ${response.status} ${response.statusText}`);
+  }
+}
\ No newline at end of file
diff --git a/front/src/lib/db/finished_event_state.ts b/front/src/lib/db/finished_event_state.ts
index 41be4c3..da82e6e 100644
--- a/front/src/lib/db/finished_event_state.ts
+++ b/front/src/lib/db/finished_event_state.ts
@@ -14,7 +14,7 @@ export async function selectFinishedEventState(eventId: number) {
     .select()
     .from(finishedEventState)
     .where(eq(finishedEventState.eventId, eventId));
-  return res[0].userIcons as UserIcon[] ?? null;
+  return res[0]?.userIcons as UserIcon[] ?? null;
 }
 
 /**
diff --git a/partykit/src/server.ts b/partykit/src/server.ts
index 7ac7d5b..c0de090 100644
--- a/partykit/src/server.ts
+++ b/partykit/src/server.ts
@@ -58,10 +58,22 @@ export default class Server implements Party.Server {
   }
 
   async onRequest(request: Party.Request) {
+    // CORS headers
+    const corsHeaders = {
+      "Access-Control-Allow-Origin": "*",
+      "Access-Control-Allow-Methods": "GET, POST, DELETE, OPTIONS",
+      "Access-Control-Allow-Headers": "Content-Type",
+    };
+
+    // Handle preflight requests
+    if (request.method === "OPTIONS") {
+      return new Response(null, { status: 200, headers: corsHeaders });
+    }
+
     const userIcons = await this.ensureLoadUserIcons();
 
     if (request.method === "GET") {
-      return new Response(JSON.stringify(userIcons));
+      return new Response(JSON.stringify(userIcons), { headers: corsHeaders });
     }
 
     if (request.method === "POST") {
@@ -76,7 +88,7 @@ export default class Server implements Party.Server {
         await this.room.storage.put("userIcons", this.userIcons);
       }
 
-      return new Response(JSON.stringify(user.id));
+      return new Response(JSON.stringify(user.id), { headers: corsHeaders });
     }
 
     if (request.method === "DELETE") {
@@ -88,10 +100,10 @@ export default class Server implements Party.Server {
       });
       await this.room.storage.put("userIcons", this.userIcons);
 
-      return new Response(null, { status: 204 });
+      return new Response(null, { status: 204, headers: corsHeaders });
     }
 
-    return new Response("Not Found", { status: 404 });
+    return new Response("Not Found", { status: 404, headers: corsHeaders });
   }
 
   async onConnect(conn: Party.Connection, _ctx: Party.ConnectionContext) {