A resolver signal converter and a resolver signal conversion method amplify and perform analogue-digital conversion on a sine wave output from a resolver; thereafter, among frequency components of the sine wave output, pass and thereby extract a predetermined bandwidth of which the center frequency is the frequency of an excitation signal, by means of a band-pass filter; sample the sine wave output while synchronizing the sine wave output with a reference signal which is based on the excitation signal; and generate a detection angle signal sine value from the sampled signal. Similarly, a detection angle signal cosine value is generated from a cosine wave output from the resolver. A detection angle is calculated based on the detection angle signal sine value and the detection angle signal cosine value. Accordingly, an influence, on an input resolver signal, of disturbance noise such as noise caused due to a magnetic field generated by a motor and switching noise caused due to PWM driving, is eliminated, and frequency dependence of arithmetic processing is eliminated. As a result, detection angle errors are reduced.