A manufacturing method of a diffraction lens (10, 100, 110) of an ICL provided with a diffraction grating having a relief pattern (30, 50, 60, 70, 80) extending concentrically on a surface (24, 102, 112) of an optical material (10, 106, 116), comprising the steps of: adopting various types of reliefs (32, 34) whose first order diffracted lights give respective focal distances different from one another for the relief pattern (30, 50, 60, 70, 80); setting up a synchronous structure where at least two reliefs (32, 34) selected from a near vision relief, an intermediate vision relief, and a distance vision relief, whose first order diffracted lights give respective focal distances different from one another, are set to overlap synchronously with each other in at least a part of an area in a radial direction of the diffraction lens (10, 100, 110), and wherein in the synchronous structure, every grating pitch of one relief having a maximum grating pitch among the reliefs (32, 34) is set up in overlap, and grating pitches of another relief are overlapped periodically, in order to obtain the relief pattern (30, 50, 60, 70, 80); and forming the resulting relief pattern (30, 50, 60, 70, 80) on the surface (24, 102, 112) of the optical material (10, 106, 116), wherein the various types of reliefs (32, 34) are arranged to satisfy a following equation: A = 2 m − NM + a / N where A is a zone constant, which is a constant for setting a zone radius of a given zone number at a certain value, of the one relief, 'a' is a zone constant of the other relief, M is a zone number of the one relief, m is a zone number of the other relief, and N is a ratio of a focal distance of the one relief relative to that of the other relief, which is expressed as: focal distance of the one relief 34 / focal distance of the other relief 32, and the zone radius is determined by the following equation using the zone constant 'a': Zone Medius = 2 m + a λf where λ is a design wavelength, and f is a focal distance, and a zone radius of the one relief is defined as follows: Zone radius = 2 M + A λ Nf; wherein the grating pitch of the one relief is larger than the grating pitch of the other relief. adopting various types of reliefs (32, 34) whose first order diffracted lights give respective focal distances different from one another for the relief pattern (30, 50, 60, 70, 80); setting up a synchronous structure where at least two reliefs (32, 34) selected from a near vision relief, an intermediate vision relief, and a distance vision relief, whose first order diffracted lights give respective focal distances different from one another, are set to overlap synchronously with each other in at least a part of an area in a radial direction of the diffraction lens (10, 100, 110), and wherein in the synchronous structure, every grating pitch of one relief having a maximum grating pitch among the reliefs (32, 34) is set up in overlap, and grating pitches of another relief are overlapped periodically, in order to obtain the relief pattern (30, 50, 60, 70, 80); and forming the resulting relief pattern (30, 50, 60, 70, 80) on the surface (24, 102, 112) of the optical material (10, 106, 116), wherein the various types of reliefs (32, 34) are arranged to satisfy a following equation: A = 2 m − NM + a / N where A is a zone constant, which is a constant for setting a zone radius of a given zone number at a certain value, of the one relief, 'a' is a zone constant of the other relief, M is a zone number of the one relief, m is a zone number of the other relief, and N is a ratio of a focal distance of the one relief relative to that of the other relief, which is expressed as: focal distance of the one relief 34 / focal distance of the other relief 32, and the zone radius is determined by the following equation using the zone constant 'a': Zone Medius = 2 m + a λf where λ is a design wavelength, and f is a focal distance, and a zone radius of the one relief is defined as follows: Zone radius = 2 M + A λ Nf; wherein the grating pitch of the one relief is larger than the grating pitch of the other relief.