An abnormality detection circuit for a resolver outputs a rotation angle signal 101 corresponding to a rotation angle of a rotor from a resolver winding 102. In the abnormality detection circuit, the resolver abnormality detection circuit applies a specified signal to one terminal of the resolver winding 102, determines whether the specified signal is superimposed on the rotation angle signal 101 outputted by an other terminal of the resolver winding 102, and detects abnormalities of the resolver based on results of the determination.