PURPOSE: To facilitate attachment/detachment and change by forming constituting parts including a ball flow passage to a unit, and also, to obviate ball jamming by vibration generated by an operation of a ball flow-down control member and a ball discharge driving means.

CONSTITUTION: A ball flow passage 73 having a ball inflow port 73a and a ball discharge port 73b is formed to a unit case 70. In this unit case 70, ball flow-down control members 61, 63, a ball discharge driving means 65 and a ball detecting means 69 are contained, by which a prize-winning ball discharge device 60 unit is constituted. On the other hand, in a supporting member for attaching this prize-winning ball discharge device 60 unit, an integrated recessed part 51 for holding a clearance S to an external form of the unit case 70 is formed, and also, in this integrated recessed part 51, a fitting boss 53 is provided projectingly, and in the unit case 70, a fitting recessed part 74 fitted to the fitting boss 53 so as to be freely turnable is formed.