A position sensor for movable body, which detects a position of a movable body which moves in a reciprocal direction, comprises; at least two portions to be detected, which are provided on one side surface of the movable body with respect to a moving direction of the movable body, and at least two detectors for detecting the portions to be detected, wherein one portion to be detected is not arranged on a line parallel to the moving direction, on which the other portion is disposed, nor arranged on a line perpendicular to the moving direction, on which the other portion is disposed, one detector corresponding to the one portion is arranged so that when the one detector detects the one portion by moving the movable body in one direction, the other portion is moved in the one direction beyond the one detector, and the other detector corresponding to the other portion is arranged so that when the other detector detects the other portion by moving the movable body in the other direction, the one portion is moved in the other direction beyond the other detector.