Provided is a slot machine capable of reducing unfairness which may result between a player who has made an investment and a player who has not made an investment and allowing a player to proceed with a game by making an investment in expectation of a jackpot at ease. Each money amount which is constant is accumulated independently of a number of bets each time betting is conducted, and upon winning a jackpot, a money amount calculated by multiplying a money amount accumulated until then by a multiplying factor based on the number of bets is provided.