PURPOSE: To prevent cooling efficiency from being lowered by branching a heat radiation part cooling piping from the middle of a water supply piping on which a cold water apparatus body is mounted, and cooling a heat radiation part of a cooler body with use of the heat radiation part cooling piping.

CONSTITUTION: A heat radiation part cooling piping 43 is divided from a water supply rider pipe 15, and a downstream end of the heat radiation part cooling piping 43 is connected with an inlet of a cooling flow passage formed in a heat radiation part cooling part 14. In contrast, an outlet of the cooling flow passage is connected with a drainage communication tube 48 connected with a drainage main tube 47 through an after-cooling water discharge branch tube 46 together with a water discharge branch tube 36. Hereby, once part of source water is directed to flow from the water supply riser pipe 15 to the heat radiation part cooling piping 43, the source water flows through the inside of a cooling flow passage of the heat radiation part cooling part 14 to cool a heat radiation part of a Peltier element B through a divided plate 14 for promotion of heat radiation. The cooling is performed with the heat radiation part cooling piping 43 branched from the middle of the water supply piping through which the source water is directed to flow, so that temperature of the heat radiation part of the cold water apparatus body is raised to prevent cooling efficiency from being lowered.