A rotation detecting device which detects the rotational state of a rotary shaft, is structured to be a device in which the number of parts is small, and the incorporation is simple. A table of orthogonal pseudo-noise codes is stored. The attendant pH change occurs rapidly and can be maintained by continuous wave light or by an appropriately pulsed light. An output image history DB is saved when output processing corresponding to the job received from the PC is performed online, whereas a job history DB is save when other output processing is performed. In other words, the self-assembled monolayer is arranged between the metal nanoparticles and the tyrosinase enzyme so as to immobilize the tyrosinase enzyme on the support.