A submergence detection power-window apparatus is provided with driving motors for moving electric-power driven opening units to opened and closed states, manual switches for manually opening/closing the electric-power driven opening units, control units for driving the motors into rotation in accordance with operations carried out on the manual switches, a submergence detector for detecting submergence of a car body and generating a submergence detection signal and a fastened/loosened seat-belt detector for detecting fastened/loosened states of a seat belt and generating a loosened-seat-belt detection signal in a loosened state of the seat belt wherein the control units drive the motors into rotation in directions to open the electric-power driven opening units when the manual switches are operated to open the electric-power driven opening units provided that a submergence detection signal is received from the submergence detector and a loosened-seat-belt detection signal is received from the fastened/loosened seat-belt detector.