PURPOSE: To eliminate rolling-up of a flexible sheet and finish beautifully an end part of a base, by a method wherein the base possesses a notched groove along a corner ridge part adjoining at least to either one side of both sides of the base and an insertion member comprised of a head part in such a form becoming flush with the surface of the flexible sheet and a leg part is inserted and stuck to the notched groove.

CONSTITUTION: A notched groove in almost a U-shaped form is provided at an angle of almost 45° along a ridge part 4 adjoining to the rear 3 of a matter obtained by covering the surface of a ligneous base 1 such as a particle board or a medium-density fiber plate or plywood or a solid plate or a flash with a flexible sheet 2 such as impregnated paper or vinyl chloride sheet by performing cut processing narower than a burying member. When a decorated insertion member 8 comprised of a head part 6 in a form of the stem of a watch so as to become flush with the surface of the flexible sheet 2 and a leg part 7 having sawteethlike protrusion on the circumferential surface and made of a solid material or an agglomerated material or plastic or rubber or aluminum or iron is stuck and fixed by inserting so that the leg part 7 is buried, a decorated processed member is obtained.