To provide a method for manufacturing a phase shift mask blank having a light translucent film or a light translucent portion having the designated phase angle and transmittance and being superior in film characteristics of chemical resistance, light resistance, and internal stress. As a result, different kinds of dowels can be driven easily without requiring extra work of changing a setup in spite of reducing the size of the device. Further, a test signal of a plurality of bits, which brings only a first test control signal to a high level while brining the remaining 2nd to nth test control signals to a low level, is input into a decoder. The disposable portion is adapted to be releasably joined with the reusable portion. If an infestation is detected, an extermination provider is arranged to apply curative treatment.