To set a position with few errors at a target position by raising the resolution of encoder signals through the use of electrical division.

When analog output signals sinθ and cosθ from an encoder head are electrically divided by a resistive division method, parameters such as the amplitudes, offsets, and phase differences of input-side signals of an electrical division circuit are detected or grasped to select such a halting position to be a halting position as to reduce errors due to their effects. Errors due to electrical division are predicted on the basis of the amplitudes, offsets, and phase differences of the signals and subtracted from position information to correct error components.