Heat treatment device

A heat treatment device (1) is provided with: a treatment container (2) for accommodating a plurality of substrates (S) subjected to a heat treatment; a substrate-holding member (3) for holding the plurality of substrates inside the treatment container (2); an induction heating coil (15) for forming an inductive loop inside the treatment container (2) and performing induction heating; a high-frequency power supply (16) for impressing high-frequency electric power to the induction heating coil (15); a gas-supply mechanism (8, 9, 10) for supplying treatment gas to the inside the treatment container (2); an exhaust mechanism (11, 12, 14) for exhausting the inside of the treatment container (2); and an inductive-heat-radiating element (7) provided between the induction heating coil (15) and the substrate-holding member (3) so as to enclose the substrate-holding member (3) inside the treatment container (2), heat being radiated by an inductive electric current formed by the inductive loop, and the substrate (S) he