A first sensor detects a rotational position of a first shaft in a noncontact fashion and generates a first output signal by phase-shifting a reference A.C. signal in accordance with the detected rotational position of the first shaft. A second sensor detects a rotational position of a second shaft in a noncontact fashion and generates a second output signal by phase-shifting the reference A.C. signal in accordance with the detected rotational position of the second shaft. First and second timing signals corresponding to phase shift amounts of the first and second output signals are output via respective output lines. Relative rotational position detection data, representing a rotational difference or amount of torsion between the two shafts, appears in a time difference between the first and second timing signals. A PWM signal, having a pulse width corresponding to a time difference between the first and second timing signals, may be output.