To effectively form a magnet resin insertion structure which closely and water tightly covers a ring magnet to serve as a driven magnet for rotating an impeller with a resin so as to protect the magnet from water, and produce a magnet pump with good rotation.

The magnet pump includes a yoke 1 where a flange part 1b is formed in one end of a cylinder part 1a in the axial direction, and a ring magnet 2 where the yoke 1 is inserted. It also has a resin bearing 3 which inserts to cover the yoke 1 and the ring magnet 2 in the inner surface of the yoke 1 and the inner side of the both end surfaces 2d, 2d of the ring magnet 2 in the axial direction. It also has a resin impeller 4 which inserts to cover the outer side surface and the outer side of the both end surfaces 2d, 2d of the ring magnet 2. The edges of the resin bearing 3 and the resin impeller 4 are water-tightly in contact with each other.