A social game and the like that can increase the fun and amusement of a team battle and enhance players' motivation to participate in or continue a game by suppressing an occurrence of any non-participation team not participating in the battle are provided. A guild status determination unit determines, for each guild, whether the guild is in an inactive state or an active state, based on a result of detecting a login state of each player. A guild integrated control unit forcibly disbands a guild (i.e. an inactive guild) determined to be in the inactive state, based on guild activity information notified from the status determination unit. A disbandment notification unit notifies each player belonging to the inactive guild, of the disbandment of the guild.