The present invention relates to a plasma etching method with which a wide-gap semiconductor substrate can be etched with high accuracy. An inert gas is supplied into a processing chamber and plasma is generated from the inert gas, a bias potential is applied to a platen on which a wide-gap semiconductor substrate is placed, thereby making ions generated by the generation of plasma from the inert gas incident on the semiconductor substrate on the platen to thereby heat the semiconductor substrate. After the temperature of the semiconductor substrate reaches an etching temperature between 200° C. and 400° C., an etching gas is supplied into the processing chamber and plasma is generated from the etching gas and a bias potential is applied to the platen, thereby etching the semiconductor substrate while maintaining the temperature of the semiconductor substrate at the etching temperature.