diff --git a/feeCalculator/src/main/java/org/example/FeeCalculator.java b/feeCalculator/src/main/java/org/example/FeeCalculator.java
index 614f798..d5da451 100644
--- a/feeCalculator/src/main/java/org/example/FeeCalculator.java
+++ b/feeCalculator/src/main/java/org/example/FeeCalculator.java
@@ -4,9 +4,9 @@ public class FeeCalculator {
 
     public static double calculateFee(Visitor visitor, TicketType ticketType) {
         if (TicketType.HALF_DAY != ticketType && TicketType.FULL_DAY != ticketType) {
-            throw new IllegalArgumentException("Invalid ticket type");
+            throw new InvalidTicketTypeException("Invalid ticket type");
         }
-        
+
         return visitor.calculateFee(ticketType);
     }
 }
diff --git a/feeCalculator/src/main/java/org/example/InvalidTicketTypeException.java b/feeCalculator/src/main/java/org/example/InvalidTicketTypeException.java
new file mode 100644
index 0000000..d4662a8
--- /dev/null
+++ b/feeCalculator/src/main/java/org/example/InvalidTicketTypeException.java
@@ -0,0 +1,7 @@
+package org.example;
+
+public class InvalidTicketTypeException extends IllegalArgumentException {
+    public InvalidTicketTypeException(String message) {
+        super(message);
+    }
+}
diff --git a/feeCalculator/src/test/java/org/example/FeeCalculatorTest.java b/feeCalculator/src/test/java/org/example/FeeCalculatorTest.java
index f45d276..982c7db 100644
--- a/feeCalculator/src/test/java/org/example/FeeCalculatorTest.java
+++ b/feeCalculator/src/test/java/org/example/FeeCalculatorTest.java
@@ -73,7 +73,7 @@ class FeeCalculatorTest {
 
         //WHEN
         assertThrows(
-                IllegalArgumentException.class,
+                InvalidTicketTypeException.class,
                 () -> FeeCalculator.calculateFee(child, TicketType.WEEK)
         );
     }
@@ -85,7 +85,7 @@ class FeeCalculatorTest {
 
         //WHEN
         assertThrows(
-                IllegalArgumentException.class,
+                InvalidTicketTypeException.class,
                 () -> FeeCalculator.calculateFee(child, TicketType.WEEK)
         );
     }