PURPOSE: To dispense with the labor for attaching an interior base material to a molded rear member by allowing the thermoplastic projection protruding from the rear surface of a member to bite in the interior base material and heating and melting the same to fix the member to the surface of the interior base material.

CONSTITUTION: A bracket (member) 2 is set to a mold 3. When an interior base material 1 is subjected to pressure molding under heating, the thermoplastic projection 2D of the member 2 is allowed to bite in the interior base material 1 at the same time to be melted and fixed. The melt of the thermoplastic projection 2D is diffused in the interior material 1 to strongly attach the member 2 to the interior base material. Therefore, the interior base material fitted with the member is produced by one process and an interior material manufacturing process is rationalized to a large extent. The attaching strength of the member becomes large.