A plasma processing method executed by a plasma processing apparatus in the present disclosure includes a first step and a second step. In the first step, the plasma processing apparatus forms a first film on the side walls of an opening in the processing target, the first film having different thicknesses along a spacing between pairs of side walls facing each other. In the second step, the plasma processing apparatus forms a second film by performing a film forming cycle once or more times after the first step, the second film having different thicknesses along the spacing between the pairs of side walls facing each other.