To prevent hydrogen chloride, dioxin, etc., from occurring, by constituting a gasket holder of a thermoplastic elastomer where soft segments not containing chlorine are mixed, and constituting a magnet body of the mixture between a magnetic substance and a thermoplastic elastomer.

An elastomer gasket 26 is constituted of a thermoplastic elastomer where soft segments mainly composed of rubber components are mixed in one or more hard segments selected from polymer not containing chlorine such as styrene or the like. For the thermoplastic elastomer, the binder material of a magnet band 28 is the same as the material of a gasket holder 27, and in the case of recycling the material as the magnet band 28, it can be made repeatedly without discrimination, and an inexpensive magnet band 28 can be obtained. Hereby, even in case that it is burned after abolition, the facility such as an incinerator or the like is not damaged by hydrogen chloride, and there is no fear of occurrence of noxious dioxin.