A plurality of game machines installed in a single hall are collectively controlled. Based on information of coin or credit consumption in a certain game machine on which a player is performing a game, this player's cumulative consumption of coin or credit is judged. As the result of this judgment, when this cumulative consumption reaches a predetermined upper limit, a return based on a predetermined return rate is executed without fail to the certain game machine on which this player is performing the game. That is, a predetermined return is guaranteed to a player who has consumed a predetermined amount, so that the player continues the game in expectation of the return. It is therefore avoidable that a player waiting for a prize for a long time keeps away from the hall.