A power operating apparatus for a vehicle door moveable between an opened position and a closed position, includes a drive mechanism provided at the inside of a vehicle body with respect to a door opening of the vehicle door to power move the vehicle door in an opening direction toward the opened position and in a closing direction toward the closed position, and a power-transmission mechanism mechanically linking the drive mechanism with the vehicle door to enable power transmission between the drive mechanism and the vehicle door. A through-opening in the body panel of the vehicle body so that the through-opening is arranged outside of the inner peripheral edge of the door opening. The power-transmission mechanism having at least a linkage portion capable of going into and out of the interior of the vehicle body. The linkage portion of the power-transmission mechanism is inserted into the through-opening, so that the locus of power movement of the linkage portion is generated outside of the inner peripheral edge of the door opening.