A method of attaching a decorative sheet in the method of bonding the decorative sheet onto the surface of an underlying material having a corner portion, the decorative sheet having a decorative layer comprising an inorganic cured material formed on one surface of a substrate sheet, the method of attaching a decorative sheet comprising a partly cutting step of preparing the decorative sheet having a cover sheet formed on the surface of the decorative layer maintaining a stripping strength, and incising the decorative layer via the cover sheet in a portion of the decorative sheet corresponding to the corner portion of the underlying material; a folding step of folding the decorative sheet along the incision in a manner that the substrate sheet is on the inside; a bonding step of bonding the substrate sheet of the decorative sheet onto the surface of the underlying material by using an adhesive in a manner that the folded portion of the decorative sheet is in agreement with the corner portion of the underlying material; an external corner-treating step of filling a putty in a gap resulting from the incision in the decorative sheet; and a stripping step of stripping the cover sheet from the decorative sheet. The method makes it possible to easily attach the decorative sheet having the decorative layer comprising an inorganic cured material to the underlying material having a corner portion without requiring any particular skill.