OIL FILLER PORT OPENING AND CLOSING DEVICE

A fuel filling aperture opening and closing device includes a closing member turned to an open position to open a fuel filling aperture by an introduction of a fuel filling nozzle. The closing member is provided with a flap member having a ring-shaped seal member, and an urging device urging the flap member to be positioned at a closed position. The seal member is provided with seal portions respectively inside and outside, and one of the inner and outer seal portions is a plate-shaped portion pressed by the urging against a projection piece bordering an opening edge portion of a pass-through opening of the fuel filling nozzle, and the other of the inner and outer seal portions is formed by an inside circumferential projecting portion and an outside circumferential projecting portion respectively pressed against the flap member.