A method for processing a target object includes arranging a first electrode and a second electrode for supporting the target object in parallel to each other in a processing chamber and processing the target object supported by the second electrode by using a plasma of a processing gas supplied into the processing chamber, the plasma being generated between the first electrode and the second electrode by applying a high frequency power between the first electrode and the second electrode. The target object includes an organic film and a photoresist layer formed on the organic film. The processing gas contains H2 gas, and the organic film is etched by a plasma containing H2 by using the photoresist layer as a mask while applying a negative DC voltage to the first electrode.