To provide a game machine capable of preventing a player from playing two or more games at a same time in a sample control.

A chair 2 is provided with a weight detecting device 20 outputting a detecting signal to a game machine 1 when a weight applied to a seat part 22 is a prescribed weight; and the game machine 1 is so formed as to receive the detecting signal from the weight detecting device 20 and is provided with a game unplayable state setting means 50, when receiving no detecting signal, making the game machine unplayable by making it impossible to insert game media, or making the operation means 30 inoperable physically or in control.