Kevin Hynes says a man walked out of his Stockholders Restaurant in Weymouth on Sunday night lugging the vault.
Surveillance tape shows the man entering a side door at the rear of the restaurant, heading down the stairs and coming back up carrying a large object wrapped in a trash bag.
No arrests have been made.
Hynes isn't saying how much money was in the safe, but he's offering a $2,500 reward for information leading to the man's arrest.
He says he's since bought an even heavier safe and bolted it to the concrete floor.
