A community member registration method is for registering a member in a community service system in which a community service server, and authentication server and a plurality of portable terminals are connected via a network. The community service server provides community service, the authentication server determines whether or not a member has authority to receive services provided by the community service server, and the portable terminals are capable of direct communication to each other. The method includes: sending a terminal identifier obtained from a portable terminal of an invitee together with a registration request from a portable terminal of an inviter to the authentication server; issuing an account of the invitee in response to the registration request in the authentication server; notifying the account to the portable terminal of the inviter from the authentication server; and sending the account from the portable terminal of the inviter to the portable terminal of the invitee.