Abstract: A method of producing a diffraction grating of borosilicate glass or barium borosilicate glass, the method comprising the steps of forming a grating on a surface of a silicon wafer the grating through the Bosch process; forming an oxide film on a surface of the grating by heating and exposure to water vapor of the silicon wafer; removing the oxide film using hydrofluoric acid; making the surface provided with the grating of the silicon wafer and a surface of a glass plate undergo anodic bonding; heating the silicon wafer and the glass plate bonded to each other; polishing a surface opposite to the boded surface of the silicon wafer and a surface opposite to the boded surface of the glass plate; and removing silicon from the glass plate by selective etching using xenon difluoride.