Abstract: A supporting structure for supporting a TV set on an armrest of a seat of an aircraft or other vehicle so that the TV set can be turned in a vertical plane between an operating position outside a cavity formed in the front portion of the armrest and a housing position within the cavity, can be turned about a vertical axis at the operating position, and can be tilted with respect to the vertical axis. The supporting structure includes a hinge mechanism provided at the front upper end of the cavity, and a turning mechanism supported on the hinge mechanism and supporting the TV set so that the TV set can be turned at the operating position in both horizontal and vertical planes. A hinge pin included in the hinge mechanism is provided at one end with a diametrical through hole expanding toward the opposite open ends.