To provide a game machine capable of inhibiting fraudulence performed by detaching a control board device from inside a casing of the game machine while facilitating the conformation work in the control board device.

The slot machine comprises the casing and a front door on the front face of the casing. A reel unit 400 with a reel device 406 mounted on a base frame 401 is mounted inside the casing, and an opening part 427 is disposed on an upper back face part of the base frame 401. A main board unit 200 is mounted in such a way that a main control device is inserted into the opening part 427 from the rear of the base frame 401. The main control device can be moved to the front side, while a pedestal device can be hardly moved to the front side via the opening part 427.