An optical connecting structure has an optical fiber, a pressing member having a circular outer cross section, and an optical member, wherein the optical member has an optical element, an optical fiber stopper structure, and an optical fiber holding groove, wherein the optical fiber stopper structure is positioned between the optical element and the optical fiber holding groove, wherein the optical fiber is inserted along the optical fiber holding groove so as to contact with the optical fiber stopper structure, and wherein the pressing member is arranged on the optical fiber holding groove mutually perpendicular, the pressing member presses the upper surface of the optical fiber to a direction of a bottom of the optical fiber holding groove, and the optical fiber and the optical element are thereby optically connected.