The present invention provides a method for producing a crystalline metal oxide thin film by first depositing a substantially amorphous metal oxide film, and thereafter, as a post treatment, exposing the film to low temperature plasma in a high frequency electric field at 180.degree. C. or less, and the crystalline metal oxide thin film produced by this method. Because the producing method according to the present invention allows a dense and homogenous crystalline metal oxide thin film to be formed onto a substrate at a low temperature without requiring active heat treatment, a metal oxide thin film having desirable characteristics can be formed without damaging the characteristics of a substrate even if the substrate has comparatively low heat resistance.