Method of producing a diffraction grating element

[Subject] Provide a manufacturing method of an optical diffraction lattice. [Means for Solution] According to the described method, a diffraction grating is manufactured using a model which has a plurality of adjoining detailed slots, and it is an inclination of the slot, It is above 20 degrees and below 70 degrees to a vertical axis of a plane of a model, the depth of a slot is 0.4 or more times of a lattice cycle of a model, described [above] type lattice cycles are 0.2 micrometer or more and 10 micrometers or less, and an escape angle of the slot is 20 degrees or less more greatly than 0 times. A step which applies an anti-adhesion layer to a manufacturing method of a diffraction grating at a described [above] type, and promotes separation of a diffraction grating from a described [above] type, A step which applies quality of a hardened material to a described [above] type, a step which hardens the substance partially at least and manufactures a diffraction grating, and a step into which the diffraction grating 10 is made to separate from a described [above] type are contained at least. [Chosen drawing] Drawing 4