Disclosed is a method for etching an insulation film of a processing target object. The method includes: in a first term, periodically switching ON and OFF of a high frequency power so as to excite a processing gas containing fluorocarbon and supplied into a processing container of a plasma processing apparatus; and in a second term subsequent to the first term, setting the high frequency power to be continuously turned ON so as to excite the processing gas supplied into the processing container. In one cycle consisting of a term where the high frequency is turned ON and a term where the high frequency power is turned OFF in the first term, the second term is longer than the term where the high frequency power is turned ON.