Provided are a decorative resin sheet that sufficiently brings together embossing property and embossment-retaining property, and a molded resin article on which an embossment excellent in design is formed and a method of manufacturing the molded resin article. The method of manufacturing a molded resin article includes the steps of: providing a resin sheet having a mold layer containing a polyolefin-based resin as a main component, followed by formation of an embossment on the resin sheet so that the embossment is formed on a surface of the mold layer; crosslinking the mold layer on which the embossment is formed so that a 100% modulus of the resin sheet at 200° C. becomes 0.02 MPa or more, which is measured in conformity with JIS K6251 (2004 version); placing the resultant resin sheet (10) in an injection molding die (20) so that the surface (11) of the mold layer faces a side from which a molten resin (30) is injected; injecting the molten resin (30) onto a side of the surface (11) of the mold layer in the injection molding die (20) to mold a molded resin article; and separating the molded resin article and the mold layer.