To improve convenience by computing the location of a mobile terminal even in an area at which signals only from two base stations or less can be utilized for location computations and enlarging a service area for location information service.

In the case that the number of base stations usable for location computations is three or more, location computations are performed by triangulation. A location computing method for two base stations and a location computing method for one base station are each provided for the case that the number of usable base stations is two or one, and either one is selected according to the number of usable base stations and used.