Abstract: A robot system for exterminating termites living in wood structural members under the floor of an architectural structure. The robot system comprises a robot including an onboard computer which is electrically connected through radio communication with a host computer located outside the robot. The robot includes a main body and is equipped with a locomotive mechanism including a pair of caterpillars located on the opposite sides of the main body. The caterpillars are driven by driving motors mounted on the robot and can be independently operated. The robot includes a mechanism for controlling the vertical positions of various sections of the main body relative to the caterpillars. A nozzle mechanism for spraying chemical or insecticide and a CCD camera are mounted on the main body. The onboard computer and host computer are operatively associated with each other to control the driving motors, the vertical position controlling mechanism, the nozzle mechanism and the CCD camera.