PURPOSE: To acquire a date of a position measured present position including dates changing in accordance with movement by position-measuring present position by way of using one piece or a plural number of artificial satellites, receiving reference position and a date from another radiocommunication device or storing the position at the time of setting clock.

CONSTITUTION: Position measuring position is found by capturing an artificial satellite by a measuring part 1, carrying out delta range measurement by way of measuring an interval between the artificial satellite and a frame marker and carrying out range rate measurement from position, speed and Doppler frequency of the artificial satellite. Thereafter, by communicating with a radiocommunication device existing at a reference position, position and date data of the reference position are acquired, time difference between the reference position and a measured position is computed and a date in consideration of date changing and the like is displayed 4. Moreover, if the position measuring position at the time of setting clock at a clock part 5 is stored in a position memory part 6, it is possible to use it as position and date information of the reference position and possible to inform the date to the other party passing the date line or a border by way of moving around the earth.