To provide a system for setting communication quantity for learning the present positions of respective mobile objects to be absolutely minimum when a target place is designated.

The base station 20 of taxis transmits a request on position data of the taxis and empty taxi data at intervals of a prescribed time by a communication equipment 11 and receives data. RAM 15 stores the latest position data which is thus obtained and position data which is stored previous time as moving situation data together with empty taxi data. When the target place is inputted on a display 16 by using a mouse 17, only a taxi having empty vehicle data and whose predicted current position predicted based on the moving situation data is near the target place is extracted. Thus, the extracted taxi is called, the latest position data are requested and communication with the mobile station is executed at need.