To provide a crime preventive device for assuring safety and crime prevention while keeping a maintenance cost to a required minimum.

An outside door 5 and an inside door 6 are provided for an access to a pachinko prize exchange dealer 1 for exchanging pachinko prize for money, where money equivalent to cash exchangeable prize is paid in exchange for the cash exchangeable prize and a private room 2 having a capacity enough to accommodate one person is provided between the outside door 5 and the inside door 6. Information for unlocking the outside door 5 is read from media for outputting an unlocking command signal from first unlocking means 23 and unlocking an electric lock 8 for the outside door. An identification code for unlocking the inside door 6 is input from a ten-key input part 24 and the unlocking command signal is output from unlocking means 25 for unlocking an electric lock 9 for the inside door when the identification code corresponds to a previously registered identification code.