A magnetic circuit includes a magnet, a first plate, and a yoke, and has a magnetic gap. The first plate and the yoke are joined to the magnet. The magnet includes first and second magnet parts. The second magnet part has a lower magnetic property than that of the first magnet part. Such a first magnet part is disposed in a vicinity of the magnetic gap. On the other hand, the second magnet part is disposed farther from the magnetic gap than the first magnet part. The first and second magnet parts are connected in parallel to each other. With this configuration, the second magnet part makes a small contribution to the magnetic flux density in the magnetic gap. Therefore, the magnetic property of the second magnet part may be low, and an inexpensive magnet can be used as the second magnet part.