A processing solution is supplied from processing-solution suppliers onto the surfaces of targets to be processed while a flow rate of the processing solution is being adjusted. The processing solution is fed from a processing-solution supply source at a specific pressure via a processing-solution pressure-up feeder. The pressure of the processing solution fed via the processing-solution pressure-up feeder is adjust to another specific pressure or more at least when the processing-solution suppliers are operating simultaneously. A flow-rate detector detects the flow rate of the processing solution supplied from each processing-solution supplier. A pressure detector detects the pressure of the processing solution fed via the processing-solution pressure-up feeder. The flow-rate adjuster and the pressure adjuster are controlled based on prestored control data and detection signals from the flow-rate detector and the pressure detector so that the same amount of processing solution is supplied to the targets from the processing-solution suppliers.