An etching method of silicon-containing oxide film is provided. The etching method includes a first step of forming an etching pattern on the silicon-containing oxide film by etching the silicon-containing oxide film using a first plasma generated from a first gas supplied to the processing vessel, according to a pattern of a mask layered on the silicon-containing oxide film, and a second step of removing a reaction product adhering to vicinity of an opening of the etching pattern and to the mask using a second plasma generated from a second gas supplied to the processing vessel, by applying a first high frequency electric power for generating plasma and a second high frequency electric power for generating bias voltage.