A decorative light-transmittance sheet type key top of a pushbutton that presents an uniform, massive and brilliant luster, which requires minimal working time in production, and wherein the work process is simplified, which is integrally formed with a transmittance plastic film (1) curved according to the shape of a top face side of the key top body (4), a decorative transmittance key top is constituted to reflect selectively light with a given wavelength and present transmittance brilliant colour by providing a cholesteric liquid crystal layer (6) made of liquid crystal polymer on a surface side and/or the back side of the film, and a manufacturing method thereof.