PURPOSE: To provide a bathtub water purifier with high purifying efficiency by arranging a filter medium in a tank filter of which the upper whole surface is made as an inflow port and installing an overflow weir between the tank filter and the prestage part of the tank filter.

CONSTITUTION: A filter chamber 14 is divided by an overflow weir 45 in right and left. One is made as a front chamber 42 whose bottom part is connected to a suction port 6 through a heater chamber 13, and the other is made as a tank filter 43 in which a filter 41 and a filter medium 44 are housed. The bottom surface of the tank filter 43 is connected to a discharge port 7 through a pump chamber 12. All the upper surface of the tank filter 43 is made as an inflow port, and also bathtub water overflowing the overflow weir 45 enters the upper part of the tank filter 43 from a prechamber 42. Therefore, after the flow of the bathtub water in the tank filter 43 comes into contact almost uniformly with all the filter medium 44 arranged in the tank filter 43, it is transferred to the pump 2 side. The flow taking a shortcut in the tank filter 43 is hardly generated to increase the purifying efficiency.