A new portable surface-climbing robot is presented for the inspection and maintenance of structures such as nuclear power plants, aircraft, bridges, and so on. The robot uses vacuum suction cups for sticking to the surface of the structure. It is capable of climbing on straight or curved surfaces in four directions, up/down or left/right in strokes of 55 millimeters. The positioning of the robot is achieved by the use of a joy-stick or a personal computer. The emphasis of this paper is on the hardware and software designs of this new surface-climbing robot. The robot is maneuvered by a microcomputer which is linked to a logical network for receiving the feedback and the status of the robot at any time. The address and data lines of the computer are used to issue control commands.