A hologram scale having a base substrate, a hologram film with a diffraction grating of a desired pitch exposed thereon, adhered to the base substrate, and with a protective substrate to protect the hologram film is manufactured by the following method: a hologram of a laser produced diffraction grating is formed on a holographic film to act as a scale. This film is applied on a central portion of a base substrate. Adhesives having moisture resistance are applied between the base and the protective substrates to essentially surround the hologram film positioned on the base substrate. The protective and the base substrates are sealed integrally by the adhesives, securing the hologram film therein so as to protect it from ambient environmental conditions.