To prevent a plate-like work in a plating tank from swinging to improve quality of plating and prevent dropout or damages of a printed circuit board during transportation. A plating tank 2a includes an upper guide rail 11 that is provided above the plating tank 2a and transports a transport hanger 15a in a moving direction and a lower guide rail 14 that is provided inside the plating tank 2a and generates an attractive force against a lower clamp 49 of the transport hanger 15a. In the plating tank 2a, an attractive force is generated while performing plate processing to pull the lower clamp 49 of the transport hanger 15a downward, thereby giving tension to a plate-like work W.