reading, with a reading device, a recording medium of the player which has recorded thereon play data for the player character, the play data including a possible number of game plays, an issuable number of times for an Al recording medium, and past play data of the player;

determining, if a remainder of the possible number of game plays is zero, that the recording medium of the player is a used recording medium, and displaying guidance for choosing renewal of the recording medium of the player;

issuing, when recording medium renewal is chosen, a new recording medium, the new recording medium storing a new possible number of game plays, the past play data of the player, and the issuable number of times for the Al recording medium;

displaying guidance asking whether or not to store play data for the partner Al character one the recording medium of the player as well as the corresponding past play data of the player character;

determining, when a choice to use the recording medium of the player as the Al recording medium is made, whether the issuable number of times for the Al recording medium is within a prescribed number of times;

issuing, when the issuable number of times for the Al recording medium is within the prescribed number of times, the recording medium of the player as the Al recording medium and writing to the recording medium of the player so that it can function as the Al recording medium;

decreasing the issuable number of times for the Al recording medium and storing the decreased issuable number of times on the new recording medium, in response to the issuance; and

ejecting the new recording medium and the Al recording medium to the outside of the game device.