An optical fiber having an elliptical lens comprises a main body (10) and two fiber pieces (15, 16) embracing one end of the main fiber body (10) therebetween and extending substantially in parallel with said main fiber body (10). The elliptical lens is formed by fused ends of the main fiber body (10) and the fiber pieces (15, 16). A method of producing an optical fiber having an elliptical lens comprises steps of arranging two fiber pieces (15, 16) substantially in parallel with and on both sides of an optical fiber (10) and adjoining and embracing one end of the optical fiber (10) and heating and fusing ends of the optical fiber (10) and the fiber pieces (15, 16) to form the elliptical lens by the fused portions thereof with the aid of surface tension. Light beams are effectively introduced into the optical fiber through the elliptical lens.