A session management system including a client environment providing server, a plurality of terminals, and a session management server, wherein the session management server includes a session monitoring unit which monitors use end time of the client environment, a client environment management unit which makes a log-out request for the execution of log-out processing of a predetermined client environment to the client environment providing server, and a state of use checking unit which checks a state of use of each the client environment, wherein the session monitoring unit notifying a request for stopping use of the client environment to the state of use checking unit when the use end time of the client environment coincides with current time, and the client environment management unit, when the client environment is in use, transmitting to the client environment providing server a log-out request of the client environment.