The object of the present invention is to provide a masking member which has good heat resistance and can be used repeatedly.To attain this object, the present invention provide a masking member made of a polymer alloy including one or more kinds of engineering plastics selected from a group consisting of methylpentene copolymer, polysulphone, polyethersulphone, polyphenylene, sulphide, polyphenylene ether, polyamideimide, polyetherimide, polyether-etherketone; and polyamide and/or polystyrene, and styrenic thermoplastic elastomer wherein said engineering plastics and said polyamide and/or polystyrene are mixed together in a weight ratio between 30:70 to 70:30, and 2 to 20 parts by weight of said styrenic thermoplastic elastomer is added in 100 parts by weight of said engineering plastics and polyamide and/or polystyrene.Said masking member has excellent moldability, a high level of mechanical strength and a good affinity with the coating film.