Abstract: A linear actuator comprises a shaft made of non-magnetic material for being reciprocatingly moved in an axial direction of the shaft, a plurality of ring-shaped moving cores which are located on the shaft and arranged in the axial direction thereof, and each of which is made of magnetic material, a first spacer made of non-magnetic material and interposed between two adjacent moving cores, a plurality of ring-shaped permanent magnets each of which is disposed on one of the respective ring-shaped moving cores and each of which includes a plurality of magnets arranged in the circumferential direction in such a manner that adjacent magnets are different in polarity, and a stationary core located around each of the permanent magnets with a clearance. The stationary core is formed with an outer ring portion formed, magnetic poles which face the permanent magnets, and legs which connect the outer ring portion and the magnetic poles. Coils are wound around the legs.