To contrive the cost down of a decorative sheet and improve bonding property between dissimilar materials as well as the shaping property of a door trim by a method wherein a packing resin layer, formed by laminating a resin mixed with metallic powder, is melted through electromagnetic induction heating and is bonded to the surface of the main body of an interior material tegether with a decorative sheet layer.

A door trim 1 is provided with an arm rest or a door pocket, provided on a decorative material 15 bonded to the door trim main body 2 and mounted on the door trim main body 2. The decorative material 15 is constituted by a method wherein a packing resin layer 17, consisting of a thermosetting resin, such as acryl or the like and having a softening point of 120-140°C, is applied on the rear surface of the decorative sheet layer 16 consisting of a cloth material and the like. Metallic powder 18, such as aluminum powder, iron powder or the like, is mixed into the packing resin layer 17. The packing resin layer 17, consisting of a thermosetting resin, is made of the same series material as the skin member 3 of the door trim main body 2 whereby melting through induction heating and the strength of bonding can be improved.