A plasma processing apparatus includes: a process chamber which accommodates a substrate to be processed; a lower electrode disposed in the process chamber; an upper electrode including an electrode plate that is detachable and discharges a process gas inside the form of shower into the process chamber; a gas supply unit including a central pipe and a edge pipe for supplying the process gas to the upper electrode; a first high frequency power source which applies high frequency power for plasma generation to the lower electrode; pressure indicators which detect pressures inside gas supply pipes; and a controller which measures a degree of consumption of the electrode plate based on the pressures detected by the pressure indicators and calculates a variation in process rate resulting due to the consumption of the electrode plate to adjust process conditions to resolve the variation in process rate.