A rotation-detecting apparatus includes a rotation-detecting means for detecting a rotation of a rotor, a rotational speed-detecting means (3) for detecting a rotational speed of the rotor and a transfer signal-generating means for generating a digitized transfer signal on the basis of items of transferred information. Either a pulsed first output waveform synchronized with rotation of the rotor, or a pseudo output waveform having a period independent of the period of the rotation of the rotor and having a first property that is different from that of the first output waveform, is selected on the basis of the rotational speed of the rotor. A second property of the output waveform selected is changed on the basis of the transfer signal. The output waveform of which the second property has been changed on the basis of the transfer signal is emitted.