A mobile communication service control system according to the present invention has a home location register 13 storing subscriber information, a switching unit 12 for sending a subscriber information inquiry signal 201 to the register 13, and a service control unit 14 for controlling a service provided for subscribers. The home location register 13 stores service information 309 necessary for a start of control of the service at the service control unit 14 and sends the service information 309 along with a response signal 308 to the subscriber information inquiry signal 201 to the switching unit 12. The switching unit 12 transfers the service information 309 received from the register 13, to the service control unit 14.