A mobile communication terminal 10A, in a process of acquiring assistance information in advance for using for a GPS position measuring at step S10, makes a judgment of whether or not the assistance information is to be acquired, prior to the GPS position measuring command by a user. When a result of this judgment is affirmative, the terminal 10A transmits an assistance information request to a position measuring assistance server 50. When the assistance information is returned from the position measuring assistance server 50 in response to this the assistance information request, in the cellular phone 10A, the assistance information is received and stored, and then prepared for a command for position measuring by the user, for which possibility of being made is higher in a short period. As a result, it is possible to perform quickly the position measuring of a current location of the mobile communication terminal.