At a time that a position detecting device is initiated, an arithmetic processing unit calculates the absolute position of a rotating shaft at the time of initiation, on the basis of first to third analog signals corresponding to first to third angles of rotation, which are detected respectively by first to third rotational angle detectors. During rotation of the rotating shaft, a current position counter detects a current absolute position of the rotating shaft by counting a number of pulses of forward rotation pulses or reverse rotation pulses, corresponding to the first angle of rotation detected by the first rotational angle detector, taking as a standard a total number of pulses corresponding to the absolute position of the rotating shaft at the time of initiation.