To improve the quality and safety of the state grasp in a tunnel and sharply reduce the load required for maintenance by providing an image receiving means of the image data transmitted from a locomotive robot and a display means of the received image data at a monitor station.

A receiver 21 receives the output image data of an ITV11 and infrared cameras 12, 13 sent from a locomotive robot 1 via radio signals and outputs the data to an ITV monitor 22 and an infrared monitor 23 respectively at a monitor station 2 outside a tunnel. The ITV monitor 22 displays the image corresponding to the image data based on the visible light, and the infrared monitor 23 displays the image corresponding to the temperature distribution in the tunnel. An operation section 25 has an operation piece instructing the automatic or manual travel mode to the locomotive robot 1 and an operation piece instructing the travel, stop, retrogradation, and slow travel or the ejection control start of a fire extinguishing bomb when a fire occurs, and it generates control commands for the instructed operations to these operation pieces.