A mobile communication system includes: a mobile station device; a first base station device to which an accessible time is set; and a second base station device. If the mobile communication system detects that a time according to the accessible time elapses and if the mobile station device is in communication with the first base station device, the mobile communication system performs a handover to switch a communication connection between the mobile station device and the first base station device to a communication connection between the mobile station device and the second communication device. Accordingly, disconnection of a call is prevented from occurring if the communication device is in communication with the first base station device when the accessible time expires.