An origin restoration mechanism includes a base unit arranged in X-Y directions to cross the axis of an operating member body of an operating member, a link mechanism arranged on the upper surface of the base unit and a pair of urging devices for urging a rotary unit of the link mechanism. The link mechanism includes the rotary unit arranged around the axis of the operating member body and our movable members arranged equidistantly around the axis of the operating member body inside the rotary unit on the surface of the base unit and having rear ends coupled rotatably to the rotary unit. Via urging forces, the portions inside of the distal end of the four movable members come into contact with different portions, respectively, of the outer surface of the operating member body located at the original position C, to hold the operating member body.