Abstract: A game system increases game play interest by making it possible for a player to acquire an item that cannot be acquired in the course of ordinary primary game play. An item acquisition information generating device is provided separately from a game device. The player inputs a code specifying the player in the item acquisition information generating device which then creates a player-specific password from item acquisition parameter data and the received player-specific code, and reports this to the player. The player inputs the reported player-specific password into the game device. The game device decodes this and separates the player-specific code from the item parameter data. The game device verifies the player-specific code, and if the result satisfies a predetermined relationship, it additionally processes the item parameter data. If the item parameter data includes winning probability data, the game device decides whether or not the player wins.