Abstract: A device for detecting a position of a moving body is provided in which a position of a moving body such as a window glass of a power window device can be detected with high accuracy, initial positions can be set without complicated adjustment, such can be realized with a simple structure and at a low cost, and assemblability can be greatly improved. In the device for detecting a position of a moving body, fixed contacts press-contact a flange portion of a ring gear from a side opposite a side at which a cover plate is disposed. Accordingly, the fixed contacts can be installed after the ring gear. In a state in which the ring gear is provisionally installed, press-contact force of the fixed contacts is not applied to the ring gear. As a result, the ring gear does not rise and positional deviation does not occur, and therefore, the assemblability can be greatly improved.