Patent ID: 8287362

Claim:
A game server for collectively controlling a game machine group comprising a plurality of game machines which are brought into a status enabling to start a game based on coin throwing or a given credit number and are given payout according to a result of said game, said game server including: return means that judges, based on information of credit consumption on a game machine where a player performs a game, cumulative credit consumption of said player and, when a judgment result is that said cumulative credit consumption reaches a predetermined upper limit, executes a return based on a predetermined return rate or based on a result of lottery for determining whether the return is to be executed, said return being executed regardless of a game result; and a first sending means for sending said game machine a signal that changes the return rate value of said game machine of said game machine group depending on return rate values of other game machines, wherein the return rate value is set by the return means in reference to a game history of the game machine and history of the return rate value change by calculating a sum of process return rates, and calculating and setting as the return rate a product of an average return rate times N, minus the sum of process return rates, so that the return rate value of the gaming machine that is within the game machine group is changed in reference to the return rate value of the game machine group, N being a predetermined number of processes.