Security cameras show the robber pulling out a gun as he walked into the store in Venice on Monday night.
The store's owner, Simon Mellor, tackled the man and the fight spilled out onto the sidewalk.
Mellor says that is when the robber pulled out a second gun.
"I wasn't happy about it (laughs). Neither of us was happy at that point. He ran, and I was like okay, he's got two - I'm not running after him. Let's call it a day," said Mellor.
The robber ran off and Mellor was not hurt.