The present invention provides a formed article, or more specifically a transparent substrate, which effectively utilizes a natural stuff and which has a low linear expansion coefficient, a high light transmittance and an appropriate level of moisture permeability. The transparent substrate includes at least an oxidized polysaccharide and has a linear expansion coefficient of 50 ppm/° C. or less at 30-150° C. and a light transmittance of 70% or more at 660 nm. Its manufacturing method includes an oxidation process in which cellulose reacts with TEMPO or its derivatives as a catalyst to be oxidized in water under the presence of a co-oxidant, along with a fiberizing process in which the oxidized cellulose is fiberized in water to form a cellulose fiber, and a substrate-forming process in which a transparent substrate is formed from a cellulose dispersion liquid containing the cellulose fiber.