An apparatus for electrostatically spray-coating a workpiece with conductive paint which includes a color changeover valve mechanism for selectively supplying conductive paint, cleaning liquid and air. A flush valve mechanism is provided for selectively supplying the cleaning liquid and the air. A first directional control valve includes an outlet and inlets. The inlets are connected to feed lines extending from the color changeover valve mechanism and the flush valve mechanism, respectively. A block line is made of an insulating material and has a first end connected to the outlet of the first directional control valve. The block line includes a second end in communication with the first end. A second directional control valve is provided having outlets and an inlet. The inlet is connected to the second end of the block line. An intermediate reservoir is connected via a feed line to one of outlets of the second directional control valve. A waste-liquid tank is connected via a first discharge line to a second outlet of the second directional control valve. A spray gun is connected via a delivery line to the intermediate reservoir. A second discharge line is branched from the delivery line via a changeover valve. A discharge line cleaning mechanism is provided for selectively supplying at least cleaning liquid and air to the second discharge line. A high voltage is applied to the conductive paint between the second directional control valve and the spray gun.