PURPOSE: To set a preferable possibility of winning a prize for a player and play shop by disposing movably a magnet near a special prize winning port and providing a drive means for selectively displacing the magnet according to the play condition.

CONSTITUTION: A magnet (permanent magnet) 64 is disposed above a swing piece 63 and a special prize winning port 41. When current is supplied to a solenoid 68, a holder 65 is extruded from the initial position forwarded by a predetermined amount with the extension of a rod 69, and under the extruded condition, an exposed part of the magnet 64 is located above the central part of an induction piece 63. When the current supply to the solenoid 68 is interrupted, the holder 65 is withdrawn to the initial position by the contraction of the rod 69, and at the contracted condition, the exposed part of the magnet 64 is encased behind a rear face member 40. A controller 91 controls the solenoid 68 for putting in and out the magnet 64 on the upper portion of the special prize winning port 41 on the basis of specified detecting signals such as program data determined in a ROM.