To make the vertical length and the horizontal length of the main body frame of a game machine variable.

This pachinko game machine is provided with a game board stored in a nearly rectangular main body frame, and a set number of game balls are discharged as prize balls when the prescribed winning state occurs via the behavior of a game ball driven into a game region formed on the front face side of the game board. A lower displacement member 20 formed by connecting a fixed section 20a and a rotary section 20b with hinges 20c, 20d is disposed at the lower side section of the main body frame 22. A side displacement member 21 formed by connecting a fixed section 21a and a rotary section 21b with hinges 21c, 21d is disposed at the side section of the main body frame 22. When the rotary section 20b of the lower displacement member 20 is rotated, the vertical length of the main body frame 22 can be changed. When the rotary section 21b of the side displacement member 21 is rotated, the horizontal length of the main body frame 22 can be changed.