Abstract: A method of manufacturing a molded product with controlled density may include preparing an upper layer outer sheath and a lower layer outer sheath of the molded product, manufacturing and preparing a filling material which forms a filling layer between the upper layer outer sheath and the lower layer outer sheath, positioning the lower layer outer sheath material in an internal space of a lower mold, disposing a temporary template on an upper portion of the lower mold to seal the internal space, and then injecting the filling material between the lower layer outer sheath material and the temporary template, removing the temporary template, and then positioning the upper layer outer sheath material on the injected filling material of the lower mold, and integrating the upper layer outer sheath material, the filling material, and the lower layer outer sheath material by heating and compression.