To easily prevent the theft of a putout object storage box in a game machine.

This theft prevention device is provided with a bar 30 provided displaceably between a lifted position and a lowered position and preventing the taking-out of the delivered object storage box 100 with its positioned in the lifted position, lowering restriction mechanisms (an engaged member/an engaging member) changing over between a lowering restriction state of restricting the bar 30 to lower from the lifted position and a lowering non-restriction state of non-restricting it, a fixing handle 70 executing an operation for making the lowering restriction mechanism the lowering restriction state from the lowering non-restriction state, and a fixing release cylinder 90 executing an operation for making the lowering restriction mechanism the lowering non-restriction state from the lowering restriction state. The fixing handle 70 and the fixing release cylinder 90 are different products.