A coin box structure includes a coin box including a box-like safe main body and a lid, a safe chamber, a shielding plate, a lock member, an actuating portion, and an actuating rod. The shielding plate has an engaging pawl and an engaging portion, is swingably supported in the lid, and is biased in a direction to shield a storage window. The lock member has an engaging protrusion and a lock pawl engaged with the engaging pawl of the shielding plate returning to a biasing direction in unloading a safe from the safe chamber to hold the shielding plate in a shielding state, and has a swinging position reversible by a tumbler mechanism. The actuating portion is brought into contact with the engaging protrusion of the lock member during sliding movement of the lid to swing the lock member and disengage the lock pawl from the engaging pawl of the shielding plate, thereby obtaining a preset state. The actuating rod swings the shielding plate against a biasing force in loading the coin box from the insertion port of the safe chamber to open the storage window and reversely swings the lock member upon engagement with the engaging portion of the shielding plate to return the lock pawl to a position at which the lock pawl is engageable with the engaging pawl of the shielding plate.