Uniformity of a plasma process on a surface of a substrate is to be improved. In a plasma processing apparatus that processes a substrate by generating plasma from a processing gas introduced in a processing container, a ratio between an introducing amount of the processing gas introduced to a center portion of the substrate received in the processing container and an introducing amount of the processing gas introduced to a peripheral portion of the substrate received in the processing container is changed during a plasma process. Accordingly, a variation in an etching rate or the like between the center portion and the peripheral portion of the substrate may be reduced. Therefore, uniformity of the plasma process on the surface of the substrate is improved.