PURPOSE: To provide a prize winning scoring device of a Japanese pinball game (pachinko) machine in which a ball going directly to a special prize winning scoring slot does not lose the chance of entering the special scoring slot even when deviated from the special scoring slot, so keeping a player in expectation of scoring.

CONSTITUTION: An obstacle member 32 which can be moved when driven by a driving source is provided above a special prize winning scoring slot 27 provided at the front edge of the bottom plate 26 of a recessed chamber 5 while an interval of at least one ball is provided between the member 32 and the bottom plate 26 so that a ball going from a movable ball receiving member 6 to the special scoring slot 27 is prevented from entering the slot 27; when predetermined conditions are met, the obstacle member 32 is actuated to allow a ball to directly enter the special scoring slot 27, and even if the obstacle member 32 prevents the ball from directly entering the special scoring slot 27, the ball is allowed to enter the special scoring slot 27 through another passage.