PURPOSE: To dress the inside of a dressing groove of a trim main body with a terminal part of a binding material in proper quantities.

CONSTITUTION: A binding material 5 is situated by a positioning plate 31. The binding plate 5 is sucked to the second pressure-contacting mold 25 for setting. The positioning plate 31 is brought into contact with its outer circumference so that the binding material 5 does not perform lateral deviation under a sucking and setting condition to the second pressure-contacting mold 25 of the binding material 5. A pressing-in plug 33 is forced to push out under a state where a trim main body 3 set up to the first pressure-contacting mold 23 and the binding material 5 set up and sucked to the second pressure-contacting mold 25 are pressure-contacted between the first pressure-contacting mold 23 and second pressure-contacting mold 25, a dressing groove 21 of the trim main body 3 is dressed with a terminal part 5a of the binding material 5 by pressing the same into the dressing groove 21.