A method for production of an identification medium, comprising: a forming step in which a code forming layer (107, 108) is formed by printing; and a joining step in which the code forming layer (107, 108) and a cholesteric liquid crystal layer are joined; wherein the identification medium comprises, in order, seen from an observing side: a cholesteric liquid crystal layer, in which a hologram is processed and circularly polarized light of a primary rotating direction is selectively reflected; an optical function layer having a structure formed by laminating a λ/4 plate and a linearly polarizing filter from the observing side, in which circularly polarized light of a secondary rotating direction opposite to the primary rotating direction selectively penetrates toward the cholesteric liquid crystal layer when natural light enters from the opposite side to the cholesteric liquid crystal layer side; and a code forming layer (107,108), in which a code constructed by at least one selected from barcodes, two-dimensional codes, OCR codes, hologram codes, and color codes that is to be read is formed, wherein a holographic image that inhibits reading of information of the code is formed by the hologram processing when the code is simultaneously read by an optical reader. a forming step in which a code forming layer (107, 108) is formed by printing; and a joining step in which the code forming layer (107, 108) and a cholesteric liquid crystal layer are joined; wherein the identification medium comprises, in order, seen from an observing side: a cholesteric liquid crystal layer, in which a hologram is processed and circularly polarized light of a primary rotating direction is selectively reflected; an optical function layer having a structure formed by laminating a λ/4 plate and a linearly polarizing filter from the observing side, in which circularly polarized light of a secondary rotating direction opposite to the primary rotating direction selectively penetrates toward the cholesteric liquid crystal layer when natural light enters from the opposite side to the cholesteric liquid crystal layer side; and a code forming layer (107,108), in which a code constructed by at least one selected from barcodes, two-dimensional codes, OCR codes, hologram codes, and color codes that is to be read is formed, wherein a holographic image that inhibits reading of information of the code is formed by the hologram processing when the code is simultaneously read by an optical reader. a cholesteric liquid crystal layer, in which a hologram is processed and circularly polarized light of a primary rotating direction is selectively reflected; an optical function layer having a structure formed by laminating a λ/4 plate and a linearly polarizing filter from the observing side, in which circularly polarized light of a secondary rotating direction opposite to the primary rotating direction selectively penetrates toward the cholesteric liquid crystal layer when natural light enters from the opposite side to the cholesteric liquid crystal layer side; and a code forming layer (107,108), in which a code constructed by at least one selected from barcodes, two-dimensional codes, OCR codes, hologram codes, and color codes that is to be read is formed, wherein a holographic image that inhibits reading of information of the code is formed by the hologram processing when the code is simultaneously read by an optical reader.