An etching method includes: preparing a compound in a processing space in which an etching target is accommodated; and etching the etching target with a mask film formed thereon, under an environment where the compound exists. The etching of the etching target includes etching the etching target under an environment where hydrogen (H) and fluorine (F) exist when the etching target contains silicon nitride (SiN), and etching the etching target under an environment where nitrogen (N), hydrogen (H), and fluorine (F) exist when the etching target contains silicon (Si). The compound includes at least one halogen element selected from a group consisting of carbon (C), chlorine (Cl), bromine (Br), and iodine (I).