An etching method is provided for selectively etching a first region of silicon oxide with respect to a second region of silicon nitride. The target object includes the second region, the first region and a mask. The etching method includes a first sequence and a second sequence. Each of sequence includes, a first step of generating a plasma of a processing gas containing a fluorocarbon gas in a processing chamber where the target object is accommodated and forming a deposit containing fluorocarbon on the target object, and a second step of etching the first region by radicals of fluorocarbon contained in the deposit. The first sequence is performed during a period including time when the second region is exposed, and an etching amount of the first region in the first sequence is smaller than an etching amount of the first region in the second sequence.