Provided is an etching method performed in a substrate-processing apparatus having: a first electrode on which a substrate is placed; and a second electrode facing the first electrode, the method comprising: a first step for introducing a first gas and halfway etching a target film into a pattern of a predetermined film on the target film formed on the substrate; a second step for introducing a second gas including Ar gas, H2 gas, and deposition gas and applying DC voltage to the second electrode to form a protective film, the second step being performed after the first step; and a third step for introducing a third gas and etching the target film, the third step being performed after the step for forming the protective film.