A resolver includes: a resolver rotor attached to a rotational shaft; an annular resolver stator that is provided on a radially outer side of the resolver rotor and that has a plurality of teeth each opposed, across a clearance, to an outer peripheral face of the resolver rotor and circumferentially arranged at given intervals; and a case member having a cylindrical fit portion to which an outer peripheral face of the resolver stator is fitted. At least three protrusions, each protruding radially outward, are formed at given circumferential intervals on the outer peripheral face of the resolver stator, so that the outer peripheral face of the resolver stator is press-fitted to an inner peripheral face of the fit portion at positions at which the protrusions are formed.