A reactor includes a coil, a magnetosensitive element attached to a lead wire of the coil, a magnetic shielding plate that shields the magnetosensitive element from a magnetic field of the coil, and a case body in which the magnetic shielding plate, the magnetosensitive element and the coil are housed. In the reactor, the magnetosensitive element and the coil are covered with a resin containing a magnetic material in the case.