A slot machine 10 is provided with a display device 30 for displaying an image and display control means for causing the display device 30 to display an image relating to a game. The slot machine 10 is further provided with a subsidiary control board 74 having the display control means packaged therein, and a scale board 76 having control means packaged therein for accepting image signals fed from the display control means, to convert the image signals into enlarged image signals having a larger display size than that displayed by the image signals, thereby to feed the enlarged image signals to the display device 30.