To provide a magnetic coupling pump device, highly accurately positioning a drive magnet in an axial direction and a radial direction.

In the magnetic coupling pump device 1, a motor rotational shaft 70, a rotor 8, a drive magnet 80 are disposed in a motor chamber 12. An impeller 2 having a driven magnet 20 is disposed in a pump chamber 11. In the motor chamber 12, an upper face part of the rotor 8 and an outer peripheral face of a large-diameter part 98 of a boss 9 constitute an annular step 92 for positioning a drive magnet, which step is concentric with respect to the motor rotational shaft 70. The drive magnet 80 is positioned in the axial direction and the radial direction by the annular step 92 for positioning the drive magnet.