A developing apparatus for developing a substrate having a coating film of a metal-containing resist formed thereon, includes: a heating part configured to support and heat the substrate; a chamber configured to cover the heating part and form a treatment space above the heating part; a gas supplier to which a developing gas containing acid is supplied; and a dispersion mechanism configured to disperse the developing gas supplied to the gas supplier and discharge the developing gas to the treatment space from a plurality of discharge ports formed at positions above the heating part.