A game system which is operable to update advertisements that are displayed when a game program is executed. The system stores a game program in a memory, receives (i.e., downloads), at predetermined times of operation, for example, on each new day the game program is executed or each time the game program is executed, updated advertising data that relates to at least one advertisement, stores the received advertising data in the memory, executes the game program stored in the memory, and outputs during the execution of the game program display data which corresponds to the stored advertisement data in accordance with the game program code. Further, instead of downloading new advertisements, plural advertisements may be prestored with the game program and only advertisement selection codes are downloaded to update the advertisements that are displayed when the game program is executed.