A pool amount (payout amount) of a jackpot award is adjusted without deteriorating individual game attractiveness of all game apparatuses even in a game system in which game apparatuses of different models are mixed.Each game progress control unit of a plurality of game apparatuses controls the progress of a game in such a manner that a ratio of an amount of payout objects paid out to a player by a payout process of the payout processing unit to an amount of bet objects received by the bet object receiving unit within a predetermined period comes closer to a normal preset payout ratio obtained by deducting a player's own pool ratio indicated by the pool ratio data stored in the pool ratio storage unit of the game apparatus concerned from a total preset payout ratio indicated by the preset payout ratio data stored in the preset payout ratio storage unit of the game apparatus concerned. These game apparatuses are provided with a pool ratio changing unit for changing the pool ratio data stored in a player's own pool ratio storage unit independent from each other.