The present invention provides a game system in which a virtual player is set in consideration of information on a place where a player plays a game. Each of game machines 3A to 3F has game machine environment information on environment of a place where the game machine is mounted. A game server 3A has character information storage device 2e for storing information 40 on environment characters according to each kind of environment information of the game machines, selects an environment character 42 associated with an environment indicated by self-machine environment information 33 of the game machines 3A and 3B participating in a game, sets the selected environment character 42 as a character of a virtual player, makes the environment character set as the character of the virtual player participate in the game, and determines operations of the environment character 42 during the game.