A backflow prevention device including an upstream shutoff valve configured to allow a user to control the water flow stream through the housing. There is a structure in which an n-channel TFT, with a third impurity region which overlaps a gate electrode, is formed in a buffer circuit, etc. The first interface controller is configured as a device, and is configured to control a connection between the first storage controller and a first host. A degree of similarity between the feature vectors in the recognition subspaces of the registered images and the input image is calculated at the detected sample points. With the constitution of the apparatus, it is possible to produce a uniform plasma in the processing container, accomplishing an even processing on even a large-diameter wafer.