There is generated a display image of a state in which a three-dimensional virtual space, including a first model and a second model to which a predetermined texture is pasted, is imaged by a virtual camera, and the generated image is displayed on a display device. The oscillator circuit comprising a voltage reference, a first current source, first capacitor, first capacitor switch, second current source, second capacitor, second capacitor switch, first comparator, second comparator and flip-flop. The digital frequency synthesis apparatus includes a phase signal and a phase-to-amplitude converter. Anti-dropping levers prevent the tubular spool shaft from dropping from the first and second holder cores by pushing a shaft inner surface of the tubular spool shaft. On the basis of the comparison result, the first image data or vector data is selected as the electronic file corresponding to the original image.