To provide a water quality-improving treatment apparatus low in the friction and eddy loss of water and efficiently converting the energy of a drive means to generate superfine air bubbles.

The water quality-improving treatment apparatus is equipped with an inflow port 8a for introducing treating water, a suction pipe 11 for sucking air, the rotor 13 fixed to a rotary shaft 9 and having axially extended polar teeth 13a successively arranged thereto in its peripheral direction and an almost annular stator 16 having a plurality of polar teeth 17b arranged at a predetermined interval with respect to the outer perypheries of a plurality of the polar teeth 13a of the rotor. A plurality of the polar teeth 13a of the rotor are formed so as to be inclined at a predetermined angle with respect to an axial direction and, when the rotary shaft 9 and the rotor 13 are rotated, air is sucked from the suction pipe 11 and treated water is allowed to flow in from the inflow port 8a and air bubbles are sheared by a plurality of the polar teeth 13a of the rotor and a plurality of the polar teeth 17b of the stator 16 to form superfine air bubbles and inflow treated water is magnetized by a drive magnetic field.