Location register, location registration system and location registration method

The invention provides a location registration system that is capable of reducing communication amount of data transmission path between a mobile communication terminal and a location register. A location registration system (10) comprises a mobile communication terminal (12) and a location register (14) for carrying out location registration of the mobile communication terminal (12). The location register (14) comprises a storage section (16) for storing the number of stays of the mobile communication terminal (12); a location registration period determination section (18) for determining a period of location registration of the mobile communication terminal (12) according to the number of stays of the mobile communication terminal (12) stored in the storage section (16); and a location registration control section (20) for transmitting the period of location registration determined by the location registration period determination section (18) to the mobile communication terminal (12), receiving location in