A mobile communication system comprises an access router configured to assign a routing address to a transient address when receiving a user data packet including the transient address is set to a source address from a mobile terminal connecting to the access router and store a correspondence between the transient address and the routing address, and a management device configured to judge whether or not a handover is carried out by judging whether or not an existing routing address assigned to the mobile terminal by other access router than the access router to which the mobile terminal connects exists, based on a unique identifier of the mobile terminal.
