The present invention is one that uniformly and simultaneously heats a plurality of cup-shaped or annular metallic bodies to improve productivity, and has a plurality of divided core parts formed by dividing an annular core; configured such that a plurality of divided end parts of the divided core part are respectively attached with metallic bodies W made of non-magnetic metal; and inductively heats the metallic bodies W through input windings provided in outer or inner circumferential parts of the metallic bodies W.