To make the use of golf course efficient by an inexpensive means and prevent an accident from occurring by equipping a ground master station with a function which judges the current position of a mobile station to which the discrimination signal of a mobile station is to be sent from the discrimination signal that a ground slave station receives.

The ground master station 10A for communication equipped with a communication and a managing function is connected by a wire communication line 10B to ground stations 10s1 to 10sn for communication which are arranged in respective areas formed by property dividing the respective holes of golf courses according to the conditions of the respective holes. The slave stations 10s1 to 10sn have a function for communicating with mobile stations 20c1 to 20cn mounted on respective golf carts in the respective communication areas by radio. Further, the ground master station 10A is equipped with the judging function which judges the current positions of the mobile stations 20c1 to 20cn to which the discrimination signals of the mobile stations 20c1 to 20cn are to be sent from the discrimination signals of the mobile stations 20c1 to 20cn that the respective ground stations 10s1 to 10sn receive and a function which displays the judged results.