To enable to obtain high speed water flow in a condition with little vibration and noise by placing plural discharging nozzles connected to a pump and facing an inlet port equipped in an inner tub of a unit flowing water from an outer tub into the inner tub and circulating water from a part of the inner tub to the outer tub.

A drain port 3 is equipped on lower face of an inner tub 2 and an almost circular inlet port 4 expanded toward inside is equipped on one side of the inner tub 2. A centrifugal pump 5 with two delivery nozzles with spiral grooves is placed in between the outer tub 1 and the inner tub 2, and the delivery nozzles are directed to the inlet port 4 of the inner tub 2. When the pump 5 is actuated for use, high speed water jets are spirally formed by the spiral grooves through two delivery nozzles and guided to the inlet port 4 to suck water in the outer tub 1 into the inner tub 2. Vortex flow generated in such a manner is further passes through the drain port 3 and in between the bottom part 1a of the outer tub 1 and the bottom part 2a of the inner tub 2 and circulates to massage a bather.