A reciprocation pump has a supply liquid-side sub-pumping chamber arranged adjacent to the supply liquid-side pumping chamber at an external side. A waste liquid-side sub-pumping chamber is arranged adjacent to the waste liquid-side pumping chamber at an external side. A rod extends through the supply liquid-side sub-pumping chamber, the supply liquid-side pumping chamber, the waste liquid-side pumping chamber and the waste liquid-side sub-pumping chamber. The rod is connected to the reciprocation mechanism and the driving source to transmit a driving force of the driving source to the reciprocation mechanism. Sealing members are arranged, respectively, in walls through which the rod extends to partition the supply liquid-side pumping chamber and the supply liquid-side sub-pumping chamber as well as the waste liquid-side pumping chamber and the waste liquid-side sub-pumping chamber.
