<p>Provided is a material for gas barrier containing cellulose fibers having an average fiber diameter of not more than 200 nm, wherein the content of the carboxyl group in a cellulose composing the cellulose fiber is 0.1 to 2 mmol/g. A molded composite having gas barrier properties such as high oxygen barrier properties can be produced by applying the material for gas barrier on a substrate and drying.</p>
