PURPOSE: To prevent loss due to a large number of prize balls in a short period from occurring in a game shop by converting a rule to a prescribed game state when a specific game state where a hit state occurs for plural times in a chained manner within a set period occurs.

CONSTITUTION: When a ball is prized to a start port 35 as a prescribed prize port, a random number value for decision read in when the ball is prized is compared with a set hit decision value by the decision comparison means 80 of a CPU. In such a case, when the ball is decided as hit, a variable display game can be executed by a variable display means 81, and a fluctuation prize device 50 can be operated based on the specification result of the variable display game. Also, the number of times of the hit state is counted by a hit state occurrence number of times counter means 82A which comprises a part of a specific game state monitoring means 82, and a count value is decided by comparing with a set limited number of times value by the number of times value comparison/decision means 82B. The occurrence of the hit state in the set period can be suppressed compulsorily by a game state regulation means 83 based on a decision result.