To provide a schedule management system wherein a schedule can be adjusted approximately in real time on the basis of an estimated time of arrival at a destination of a user moving by an automobile.

In a schedule management system 10, a navigation device in an automobile 110 of each user 100 calculates an estimated time of arrival at a destination and transmits the estimated time to a schedule management center 200 via a network 300 at intervals of a prescribed time, and the schedule management center generates schedule adjustment information by delaying start times of individual schedules of users which are preliminarily registered, and transmits the schedule adjustment information to transmission and reception parts of automobiles of the user and the other participant users in the case that the estimated time of arrival sent from the automobile of the user is later than start times of the schedules.