PURPOSE: To provide a magnet-driven axial flow pump of in-line type where the normal direction flow and the reverse direction flow can be obtained by changing the rotating direction of the pump.

CONSTITUTION: A straight pipe type casing 9, a body of revolution which supported by the outer circumference of the casing and rotated by a prime mover, an outer magnet 17 provided on the body of revolution, a main shaft 18 which is arranged in the casing and whose ends are supported by the casing, and an inner magnet 23 which is supported on the main shaft, opposite to each other across the outer magnet and the casing, and rotated around the main shaft are provided. This magnet-driven axial flow pump is provided with an axial flow type impeller 24 which is arranged on the main shaft close to the inner magnet and connected to the inner magnet.