A system that remotely controls a mobile body includes a guideway (i.e., balanced feeder line) for guiding the mobile body to its destination, and a coupling device provided on the mobile body for transmitting and receiving control information to control movement of the mobile body along the guideway. The coupling device includes a first loop antenna and a second loop antenna that are cross-connected to each other. A distance from the center of the balanced feeder line to the center of the first loop antenna is less than a distance from the center of the balanced feeder line to the center of the second loop antenna. The system can operate with an extremely low power of emission with a weak electric field intensity of a radio wave for controlling the movement of the mobile body.