To provide a locking device in a game machine facilitating pull-out/insertion of a key relative to a cylinder lock and facilitating unlocking/locking of a front frame and a glass frame.

This locking device 3 in the Pachinko machine 1 is provided with the cylinder lock 4 having a keyhole turning part 42, and a lock mechanism 5 capable of locking and unlocking the front frame 21 and the glass door 22. The keyhole turning part 42 is provided with a turning cam 6, when being in an initial position, allowing the key 43 to be pulled out/inserted and engaged with the lock mechanism 5. The turning cam 6 is directly energized to turn by a cam energizing means 7 so that the keyhole turning part 42 returns to its initial position 400. The lock mechanism 5 is so constituted that, when the keyhole turning part 42 is in the initial position 400, locks the front frame 21 to the glass door 22, when the key 43 turns in a first direction 401, unlocks the front frame 21, and when the key 43 turns in a second direction 402, unlocks the glass door 22.