A radio communicative region measuring system is provided for measuring a region in a workspace, in which radio communication can be performed. The system has a mobile object that carries a radio transmitter for measuring a radio communicative region. A radio receiver for measuring a radio communicative region is provided in the workspace. A position detecting system such as an ultrasonic tag operating unit is provided, which included a transmitter to be carried by the mobile object and a plurality of receivers provided in the workplace. Based on radio signal received by the radio receiver and positional information provided by the position detecting system, a region in which radio communication can be performed between the radio transmitter and the radio receiver is determined.