To make it possible to constitute a prize winning device capable of being installed at an arbitrary position to provide interest in different ways by attaching a control substrate in a pachinko game machine, which has been attached to the rear of the game plate, in a position vertical with the game plate.

The area available for a control substrate 55 mounted on a connector 53 to be attached can be small because the substrate is attached vertically against a game plate. Therefore, a prize winning device protruding to the rear of the game plate can be installed in any of the area in the game plate without being interfered with the control substrate 55, being different from conventional arrangements. For this reason, the prize winning device may be installed below the game plate, for example, so that different game patterns may be adopted. In addition, this construction allows the front and rear surfaces of the control substrate 55 to be seen through a main transparent cover 56, hence it is possible to discover whether a jumper wire has been placed on the rear side, which is an unlawful action, can be discovered without removing the control substrate 55.