NOVELTY - A gas barrier film (1a,1b) comprises gas barrier layer (3) containing silicon, oxygen and carbon as main element, provided on surface(s) of base material (1). The carbon distribution curve of the gas barrier film exhibits the relationship with ratio of content of carbon atom with respect to total content of silicon atom, oxygen atom and carbon atom, and has local maximum value of 2 or more with different magnitude and plurality of local maximum values appears periodically on carbon distribution curve with respect to change of distance from surface of gas barrier layer.    USE - Gas barrier film used for gas shutoff of electronic device e.g. liquid crystal, organic electroluminescent element, solar cell and electronic paper.    ADVANTAGE - The gas barrier film has excellent transparency and flexibility and reduced deterioration. The gas barrier film is efficiently manufactured with high productivity.    DETAILED DESCRIPTION - A gas barrier film comprises gas barrier layer containing silicon, oxygen and carbon as main element, provided on surface(s) of base material. The carbon distribution curve of the gas barrier film exhibits the relationship with ratio of content of carbon atom with respect to total content of silicon atom, oxygen atom and carbon atom, and has local maximum value of 2 or more with different magnitude and plurality of local maximum values appears periodically on carbon distribution curve with respect to change of distance from surface of gas barrier layer, based on element distribution measurement using X-ray photoelectron spectroscopy in depth direction of distribution curve of each main element of gas barrier layer and distance from the surface of the gas barrier layer in the layer thickness direction of gas barrier layer. An INDEPENDENT CLAIM is included for manufacture of gas barrier film, which involves forming gas barrier layer on base material using plasma chemical vapor deposition method.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of gas barrier film.    Base material (1)    Gas barrier film (1a,1b)    Smooth layer (2)    Gas barrier layer (3)    Overcoat layer (5)