The incident happened Wednesday night at Cousins Liquor on Harbor Boulevard, according to the Fountain Valley Police Department.
The owner, Jacko Sadek, was behind the counter when a man dressed in black came up with what looked like a gun and demanded money.
That's when Sadek said he noticed the gun didn't look real - so he pulled his own gun out.
"It looks like a kid and the gun looks so fake... like a plastic toy. At that time, I pulled my gun... and he just ran away," he said.
The would-be robber took off and ran to the back alley where a car was waiting, police said.
The store's owner says he was able to remain calm because two years ago he was robbed at gunpoint as well.