<p>The present invention uses a purification unit (4) to purify raw water supplied from a raw water supply unit (2) and passes the result to a purified water supply pathway (3). The present invention is provided with at least: a reservoir unit (5) that can retain at least the water in the purified water supply pathway (3); a sterilizing fluid generating unit (8) that can generate a sterilizing fluid containing a sterilizing component and supply the result into the purified water supply pathway (3); and a sterilizing component decomposition unit (81) that, at the completion of sterilization, recovers the sterilizing fluid in the purified water supply pathway (3) and decomposes the sterilizing component. Also, during sterilization of the purified water supply pathway (3), the water in the purified water supply pathway (3) is transferred to the reservoir unit (5). This transferred water is used as raw water after sterilization.</p>
