A substrate processing method effectively suppresses non-uniformity in deposition degree on a surface of a substrate. The substrate processing method includes depositing a deposit on a sidewall of each opening of a resist pattern, which is formed on an antireflection film on an etching target film of the substrate and is provided with a plurality of openings, before etching the etching target film of the substrate. Plasma is generated in the depositing process by introducing a CHF-based gas into the processing chamber at a flow rate equal to or higher than about 1000 sccm while a pressure in the processing chamber is set to equal to or higher than about 100 mTorr.