A plasma processing method capable of reducing an amount of deposit adhering to an upper electrode or removing the deposit from the upper electrode is provided. In the plasma processing method, the upper electrode of a capacitively coupled plasma processing apparatus is cooled. A supporting table including a lower electrode is provided within a chamber of the plasma processing apparatus. The upper electrode is provided above the supporting table. During the cooling of the upper electrode, a film of a substrate is etched by plasma generated within the chamber. The substrate is placed on the supporting table during the etching of the film. A negative bias voltage is applied to the upper electrode while the etching is being performed.