<p>The leakage of high voltage to the outside is cut off by use of an arm of a paint robot. A tank (25) is mounted on the robot arm (1). The tank (25) is filled with water for use as an operating liquid. The water is supplied to a paint cartridge (4) by use of a pump (24) controlled by a controller (40). Water ejected from the pump (24) under pressure is supplied to the paint cartridge (4) by use of a water-conducting tube (12). A high voltage generator (45) and a breeder resistance (46) are provided on the tank (25). High voltage generated in the high voltage generator (45) is supplied to an electrostatic paint device (2) via water. A nozzle (32) communicated with a water (an operating liquid) source (34) is relatively connected with a main pipe (23) so as to refill the tank (25) with water. During the generation of high voltage by the high voltage generator (45), the nozzle (32) and the main pipe (23) are separated from each other and electric insulation between the nozzle (32) and the main pipe (23) is maintained.</p>
