An FSK signal receiving device is constituted by a first phase shifting circuit for applying a first phase shift to a first reception base band signal of first and second reception base band signals having orthogonal phases to generate a third base band signal, and generating a fourth base band signal having a phase orthogonal to the phase of the third base band signal, a second phase shifting circuit for applying the first phase shift to the second base band signal to generate a fifth reception base band signal, and a logical gate circuit for performing an exclusive OR operation on the third and fourth base band signals to obtain a first output signal, on the third and fifth base signals to obtain a second output signal, and on the first and second output signals to generate a detection signal.