A deposition method includes forming a nitride film on a surface of a substrate; and performing, after the depositing, plasma purging supplying a noble gas activated as a plasma. The forming of the nitride film includes a) forming adsorption inhibitors on the surface of the substrate, by supplying a chlorine gas activated by a plasma and by causing the activated chlorine gas to be adsorbed on the surface of the substrate; b) causing a raw material gas, containing silicon and chlorine or a metal and chlorine, to be adsorbed on a region in the surface of the substrate on which the adsorption inhibitors are not present, by supplying the raw material gas on the surface of the substrate; and c) depositing the nitride film on the surface of the substrate, by supplying a nitriding gas to cause the raw material gas to be reacted with the nitriding gas.