The invention relates to a molten metal plating apparatus comprising a roller rotatably supported by a bearing in a molten metal bath, the roller having a shaft sliding portion, the bearing having a sliding portion, both the shaft sliding portion and the sliding portion being made of ceramic sintered body, at least one of both the shaft of the roller and the bearing being made of a ceramic sintered body containing a solid lubricating material. The invention also relates to a die casting machine having a sleeve and a plunger tip both made of ceramic sintered bodies at least one of which contains a solid lubricating material. The bearing for the roller, the sleeve and the tip may be formed of a composite body having a ceramic sintered body portion and and a metal portion secured and fitted thereto by an intermediate member which is elastically and plastically deformed at the time of the usage. The composite structure formed by fitting is usable for other applications.