A game device (A1) registers at least one game character from among a plurality of prepared game characters with an entity managed in a virtual space by a player, and engages in a competition with another game device (B1), using a game character that is specified by a player from among registered game characters. A server device (3) computes a degree of popularity for each of game character on the basis of information sent from a plurality of game devices (A1, B1), and determines registration fees necessary for registering game characters with players' entities on the basis of degrees of popularity. The registration fee list is delivered to each game device when the game device is activated.