In the related art, in a control device driving an opening/closing body of a vehicle such as a sliding door, there is a device to detect a movement position of the opening/closing body by counting (edge of) pulse signals synchronized with a movement of the opening/closing body.  For example, a pulse sensor using a Hall element is used in a power sliding door device disclosed in JP2005-76319A (Reference 1).  That is, generally, such a pulse sensor is provided with a rotation body that rotates in synchronization with the movement of the opening/closing body, and a pair of Hall elements facing a magnet provided in the rotation body on a periphery of the rotation body.  For the pulse signal with two phases in which phases output from these two Hall elements are deviated from each other by 90°, by detecting the edge thereof, a movement direction and a movement position of the opening/closing body can be detected. 
In a case where a new edge is no longer detected for the pulse signal, it is possible to determine that the opening/closing body has stopped.  Thereby, without providing an additional configuration such as a limit switch, it is possible to detect that the opening/closing body reaches a terminating end of a movement range, that is, reaches a fully open or fully closed position. 
However, the resolution of pulse sensors has improved in recent years.  Therefore, in the detection method of the related art, an opening/closing body reaching a terminating end of a movement range may not be detected.  That is, a vibration caused by an elastic deformation of a sealing member provided on a periphery of a sliding door, rattling of mechanical components, or torque variation of a motor as a driving source or the like may occur in the opening/closing body after a stop thereof.  In a case where a pulse sensor with a high resolution is used, there is a problem that minute vibrations may be read as a movement position change of the opening/closing body. 
That is, in the related art, as long as new edges of the pulse signals are continuously detected, a stop of the opening/closing body is not detected.  Specifically, in order to simplify, such a problem is significant in a configuration using the pulse signal that a rotation sensor provided in the motor outputs.  Since there is a problem that the configuration is complicated in a case of adding a new decoder in order to avoid this problem, there is room for improvement in this regard.