There is provided a lensed optical fiber (20) in which a lens is formed on the end face of an optical fiber to enhance the efficiency of optical coupling with a light beam. The tip end portion of an optical fiber (21) is formed with a lens (26) formed into a wedge shape having two slant portions (24) symmetrical with respect to an axis (Ac) of a core (22) and a plane portion (25) perpendicular to the axis of the core. <IMAGE>