For control of crystal grain size in a spin-valve film, a lithographic technique is needed which exhibits high productivity and enabling formation of a pattern at about 10 nm. The control section determines whether to gradually discharge the battery in accordance with the detected illuminance or to rapidly discharge the battery, and the determination is made on the basis of the temperature detected from the temperature detection section and the battery voltage detected from the voltage detection section. A connector is disposed on the tube at the first end. Moreover, the control circuit reads data specified by the command from the nonvolatile memory and stores it in the buffer memory as preread data.