Information about a plurality of participation rewards to be given upon participation in a game event during each unit period in a period in which the event is held, is presented to a user. An upper limit number of unit periods for giving, and the reward contents, are set in advance. In accordance with event participation, participation rewards corresponding to the unit periods in which the participation timings are included are given to the user. The event advancement status is updated on the basis of the event participation by each user. If an ending condition is satisfied, event advancement is ended. If the number of times the unit period has come until the end of the event since the start thereof is smaller than the upper limit number of unit periods in which the rewards can be given, at least one of non-given participation rewards is given to the user.