PURPOSE: To surely prevent unauthorized use by providing a reset switch which immediately applies latching when a detection signal of opening is received from a detection switch notwithstanding that no opening command signal is detected by a proper operation judging means and releases the latching.

CONSTITUTION: When the movable blade piece of a variable winning device is opened compulsorily, a detection switch 13 is operated notwithstanding that no opening command signal is outputted from a one-shot multivibrator 40, and it is received by a HAND gate 45, and output is inverted, and a flip-flop 46 is latched. Also, the signal is received from the detection switch 25 by a HAND gate 49 even when the opening/closing door of another variable winning device is opened compulsorily, and similarly, the flip-flop 46 is latched. A relay coil 55 is excited, and a normally-closed relay contact 56 is opened, and a motor 27 is stopped, which disables the launching of a hit ball. Also, the latching is released by operating the reset switch 47, and the normally-closed relay contact 56 is returned to an original closed state, and the launching of the hit ball can be restarted.