The present invention provides a communication system and a communication method for linking the switching of a transmission path with the switching of an application according to the change of a communication condition caused by the movement of a user in a mobile environment. A change of the communication condition caused by the movement of the user is always monitored and the transmission path is switched according to the state change of the transmission path. Here, the state of the transmission path between the terminal and the communication counter part terminal is obtained and compared to a priority reference for each of the applications, thereby selecting a transmission path appropriate for the application becomes possible and a service in corresponding to the communication condition can be provided by changing a content to that appropriate for the transmission path, simultaneously.