An etching method including an etching step of bringing an etching gas which contains nitrosyl fluoride and has been converted into plasma into contact with a member to be etched (9) having an etching object and a non-etching object, and selectively etching the etching object as compared with the non-etching object. The etching step is performed in a chamber (7) containing the member to be etched (9) using a remote plasma generation device (16) provided outside the chamber (7) as a plasma generation source. The concentration of nitrosyl fluoride in the etching gas is 0.3 vol % or more, the temperature condition of the etching step is 0° C. to 250° C., and the pressure condition of the etching step is 100 Pa or more and 3 kPa or less. The etching object includes silicon nitride. Also disclosed is a method for producing a semiconductor device using the etching method.