Correction method for sensor output

A correction method for a sensor output, which applies light to a measuring object and carries out measurements by receiving light reflected from a detection subject portion by a sensor, wherein

• said sensor lacking linearity in an output thereof in response to the quantity of received light, and
• said method comprises a linearizing process that corrects the sensor output so that the output from said sensor in response to a variation in the quantity of received light is made proportional to the quantity of received light,
• wherein said linearizing process comprises the following processes (A) and (B):
• (A) a process in which a photodetector having linearity in an output thereof in response to the quantity of received light is arranged so that light to be made incident on the sensor is simultaneously made incident on said photodetector, and upon variation in the quantity of incident light, a relationship between the sensor output and the output of said photodetector is stored as linearizing data;
• and
• (B) a process in which, upon measurement of a measuring object, the resulting sensor output is corrected and made proportional to the output of said photodetector based upon said linearizing data.