PURPOSE: To inexpensively obtain a trim by integrally bonding cloth to the main body of the interior product without providing an engaging jig such as a fastener by applying a high frequency magnetic field between both high frequency electromagnetic heating electrodes while holding a mesh like article between said electrodes under pressure.

CONSTITUTION: A ring-shaped metal net D as a metal mesh like article is set to the outer periphery of an armrest part b1 being a cloth bonding part. A trim main body B to which the metal net D and cloth C are set is placed on the lower high frequency electromagnetic heating electrode 1 of a high frequency electromagnetic heating apparatus equipped with lower end upper high frequency electromagnetic heating electrodes 1, 2 integrated up and down in such a state that the horizontal posture thereof is held to be set between both electrodes 1, 2. A high frequency magnetic field is applied between the high frequency electromagnetic heating electrodes 1, 2 to heat the metal net D. By this method, the resin of the outer periphery of the armrest part b1 of the trim main body D made of a polyolefinic resin is melted by the heat of the metal net D. The molten resin is infiltrated in the outer periphery of the cloth C to obtain a door trim A wherein the cloth C is integrally bonded to the trim main body B.