Provided is an opening/closing apparatus for vehicles which reduces the size and weight by reducing the number of components and suppresses rattling of an opening/closing body through sliding resistance of cables. A guide plate is provided between a drum and a pulley to direct orientation of a closing-side cable and an opening-side cable drawn out from the drum to the pulley. The guide plate has a sliding contact curved surface with which the cables and are brought into sliding contact, and the guide plate is provided on a swing arm of a pulley case in which the pulley is rotatably housed.