To improve an external appearance and bounding with FRP without applying primer processing by a method wherein a styrene-based and/or modified olefin-based resin layer is directly bonded with main member and then transparent or semitransparent thermoplastic resin having the specified total light transmittance is laminated onto the outermost layer of the bonded resin layer.

As a bonded reins layer 2 except the outermost layer 1, styrene- based resin and/or modified olefin-based resin are sued. As the modified olefin- based resin, mollified polypropylene, which is excellent in bonding with FRP (fiber reinforced thermoplastic resin) as a main member 3, or the like is preferable. The FRP contains, before the reaction takes place by thermal pressure, a large amount of styrene monomer for reacting with the resin under the state that both the joint surfaces of the FRP and the resin are melted, resulting in making primer processing unnecessary. As the material of the outermost layer 1, transparent or semitransparent general purpose thermoplastic resin having the total light transmittance of 20% or more is used for bonding and further obtaining a product having a splended external appearance with deep taste.