PURPOSE: To attain effective data feed in a short time by utilizing a time between transmission and reception of a usual data between a fixed station and a mobile station so as to discriminate a current position of the travelling object.

CONSTITUTION: When a radio wave is sent sequentially from radio equipments 9A-9C of each fixed station side, a data terminal equipment 3 of a fork lift 1B identifies respectively a received electric field strength of a radio wave received sequentially by a radio equipment 2 and specifies a radio equipment in the radio equipments 9A-9C giving the highest reception electric field strength. The data terminal equipment 3 of the fork lift 1B sends an identification data of the specified radio equipment 9B from the radio equipment 2 as a position data by means of a radio wave. Thus, a host computer 14 discriminates it that the current position of the fork lift 1B is a position close to the radio equipment 9B of the fixed station side based on the position data of the radio wave sent from the fork lift 1B.