diff --git a/lambdas/step_function_invoker/src/index.py b/lambdas/step_function_invoker/src/index.py
index 67a1074..bfb36e9 100644
--- a/lambdas/step_function_invoker/src/index.py
+++ b/lambdas/step_function_invoker/src/index.py
@@ -17,7 +17,7 @@ def lambda_handler(event, context):
 
     try:
         state_machine_execution_result = step_functions_client.start_execution(
-            stateMachineArn=STATE_MACHINE_ARN,
+            stateMachineArn=STATE_MACHINE_ARN[0],
             input=event,
         )