A slide door opening and closing apparatus for a vehicle includes a drive pulley, a driven pulley, a pulling member extending between the drive pulley and the driven pulley and connected to a slide door, a drive side idle pulley provided in the vicinity of the drive pulley for guiding the pulling member extending at an inner side of the vehicle toward an outer side of the vehicle via the driven pulley, a housing including an opening portion through which the pulling member guided by the drive side idle pulley is inserted, and a partition provided at the opening portion of the housing, the partition interposed between the pulling member at the inner side of the vehicle and the pulling member guided toward the outer side of the vehicle via the driven pulley.