An electric power-feeding structure for feeding electric power to a moving body which is driven to be raised or lowered, includes: an arm having a distal end connected to the moving body movably in a horizontal direction and a proximal end rotatably driven to swing, to thereby drive the raising or lowering of the moving body. An electrical wire is routed alongside the arm, and one end of the electrical wire extending from the distal end is connected to the moving body. In a vicinity of a rotating shaft of the arm, the electrical wire is fixed to the arm at a first fixing point and to a base for supporting the arm at a second fixing point. The first fixing point is provided on a straight line defined by the rotating shaft and the second fixing point when the arm is at an intermediate position of its swinging range.