The rotating speed of an output shaft of a door opening and closing motor actuating a sliding door is monitored, and whether a fluctuation value of the rotating speed is equal to or more than a first determination threshold value is determined (step S310). A second determination threshold value having a pinching detecting sensitivity that is higher than the first determination threshold value is set. When it is determined that the shift lever of the transmission is in a P position, or a foot brake is operating, or a parking brake is operating, whether the fluctuation value of the rotating speed is equal to or more than the second determination threshold value is determined (step S360). If the fluctuation value of the rotating speed is equal to or more than each of the determination threshold values, the sliding door is actuated in an opening direction (step S320).