To execute the instruction as to whether ball hitting is permissible or not in such an occasion of the occurrence of a fog.

This system has a ball hitting instruction means capable of discriminating whether a cart Ka and other cart Kb exist within a prescribed distance is executed in accordance with the cart transmission data transmitted from the other cart Kb circulating in a cart road R to a control house CB and capable of giving an instruction whether the ball hitting is permissible or not to the craft Ka in accordance with the result of the discrimination. The system also has the ball hitting instruction means capable of discriminating whether the other cart Kb exists within the prescribed distance from the cart Ka in accordance with the cart transmission data KTb transmitted from the other cart Kb circulating in the cart road R and capable of giving the instruction as to whether the ball hitting is permissible or not to the cart Ka in accordance with the result of the discrimination.