diff --git a/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/builder/DefaultArbitraryBuilder.java b/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/builder/DefaultArbitraryBuilder.java
index 2a39516f1..225cc76bf 100644
--- a/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/builder/DefaultArbitraryBuilder.java
+++ b/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/builder/DefaultArbitraryBuilder.java
@@ -245,7 +245,7 @@ public ArbitraryBuilder<T> size(String expression, int minSize, int maxSize) {
 	@Override
 	public ArbitraryBuilder<T> size(PropertySelector propertySelector, int minSize, int maxSize) {
 		if (minSize > maxSize) {
-			throw new IllegalArgumentException("should be min > max, min : " + minSize + " max : " + maxSize);
+			throw new IllegalArgumentException("should be min <= max, min : " + minSize + " max : " + maxSize);
 		}
 
 		List<NextNodePredicate> nextNodePredicates = toMonkeyExpression(propertySelector).toNextNodePredicate();
diff --git a/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/customizer/InnerSpec.java b/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/customizer/InnerSpec.java
index 1699b01fb..5255a73f2 100644
--- a/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/customizer/InnerSpec.java
+++ b/fixture-monkey/src/main/java/com/navercorp/fixturemonkey/customizer/InnerSpec.java
@@ -114,7 +114,7 @@ public InnerSpec inner(InnerSpec innerSpec) {
 	 */
 	public InnerSpec size(int minSize, int maxSize) {
 		if (minSize > maxSize) {
-			throw new IllegalArgumentException("should be min > max, min : " + minSize + " max : " + maxSize);
+			throw new IllegalArgumentException("should be min <= max, min : " + minSize + " max : " + maxSize);
 		}
 
 		this.state.setContainerInfoSnapshot(
diff --git a/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/adapter/ValueProjectionCustomizationTest.java b/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/adapter/ValueProjectionCustomizationTest.java
index 1ab945586..c9e86ba28 100644
--- a/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/adapter/ValueProjectionCustomizationTest.java
+++ b/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/adapter/ValueProjectionCustomizationTest.java
@@ -1058,7 +1058,7 @@ void sizeMinMax() {
 	void sizeMinIsBiggerThanMax() {
 		thenThrownBy(() -> SUT.giveMeBuilder(StringListHolder.class).size("values", 5, 1).sample())
 			.isExactlyInstanceOf(IllegalArgumentException.class)
-			.hasMessageContaining("should be min > max");
+			.hasMessageContaining("should be min <= max");
 	}
 
 	@Property
diff --git a/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/test/FixtureMonkeyTest.java b/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/test/FixtureMonkeyTest.java
index ba9ddf748..7418182d3 100644
--- a/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/test/FixtureMonkeyTest.java
+++ b/fixture-monkey/src/test/java/com/navercorp/fixturemonkey/test/FixtureMonkeyTest.java
@@ -388,7 +388,7 @@ void sizeMinIsBiggerThanMax() {
 		// when
 		thenThrownBy(() -> SUT.giveMeBuilder(ComplexObject.class).size("strList", 5, 1).sample())
 			.isExactlyInstanceOf(IllegalArgumentException.class)
-			.hasMessageContaining("should be min > max");
+			.hasMessageContaining("should be min <= max");
 	}
 
 	@Example