To efficiently being a frequency by which a position register request is transmitted by referring to a frequency selection table based on position data of mobile radio equipment and selecting the frequency.
A frequency selecting part 3 obtains a straight line distance between a base station arrangement position and a present position by the latitude and longitude data expressing the present position, which is read from a position data receiving part 2, and by the value of the base station arrangement position field of the frequency selection table 4. Continuously, the obtained straight line distance is compared with a communication area radius, it is judged that the present position is inside a base station communication area when the straight distance is shorter and the frequency to be used is read from the frequency selection table 4. When the desired base station is found, the frequency selecting part 3 displays the used frequency obtained by referring to the table 4 in a display part 5.
ARIGA MASAYOSHI
NAGIRA TSUMORU
