A manufacturing method of a diffraction lens of an ICL provided with a diffraction grating having a relief pattern extending concentrically on a surface of an optical material , comprising the steps of: adopting various types of reliefs whose first order diffracted lights give respective focal distances different from one another for the relief pattern ; setting up a synchronous structure where at least two reliefs 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 , and wherein in the synchronous structure, every grating pitch of one relief having a maximum grating pitch among the reliefs is set up in overlap, and grating pitches of another relief are overlapped periodically, in order to obtain the relief pattern ; and forming the resulting relief pattern on the surface of the optical material , wherein the various types of reliefs 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 whose first order diffracted lights give respective focal distances different from one another for the relief pattern ; setting up a synchronous structure where at least two reliefs 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 , and wherein in the synchronous structure, every grating pitch of one relief having a maximum grating pitch among the reliefs is set up in overlap, and grating pitches of another relief are overlapped periodically, in order to obtain the relief pattern ; and forming the resulting relief pattern on the surface of the optical material , wherein the various types of reliefs 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 . <EOS>