Abstract: A roulette-like ball game machine has a rotary disk with a plurality of pockets arranged in a peripheral direction and assigned a number respectively, and a guide circle provided around the rotary disk at a somewhat higher position and joining to the rotary disk through an inclined surface. While the rotary disk is turned, a ball rolled along the guide circle falls inside and enters one of the pockets to decide a prize number. In such a ball game machine, a plurality of operation stands are arranged around the guide circle, the rotary disk is formed in an annular shape having a large inner diameter, a large-sized picture surface is provided within the central space of the rotary disk and various pictures are projected on the picture surface by an image projector.