PURPOSE: To provide a water purifying apparatus constituted so that the regeneration efficiency of an adsorbent bed is enhanced and the prefilter provided to a purifying tank can be regenerated.

CONSTITUTION: In a water purifying apparatus equipped with a purifying tank 13 having adsorbent beds 13a, 13b composed of active carbon built therein, a hot water producing tank 11 and a regeneration tank 14 separating the impurities adsorbed on the adsorbent beds 13a, 13b and constituted so that water is purified in the purifying tank 13 and the hot water of the hot water producing tank 11 is supplied to the purifying tank 13 and the regeneration tank 14 to separate the impurities of the adsorbent beds 14a, 14b to regenerate the adsorbent beds 13a, 13b and hot water containing impurities is drained through a fifth solenoid valve 12 to regenerate the adsorbent beds 13a, 13b, the regeneration tank 14 is arranged inside the adsorbent beds 13a, 13b of the purifying tank 13 and, therefore, the water passed through the adsorbent beds 13a, 13b is gathered in the regeneration tank 14 having a water passing cross section smaller than that of the adsorbent beds 13a, 13b to efficiently regenerate the adsorbent beds 13a, 13b.