CONCENTRATION MEASURING INSTRUMENT

摘要

To provide a measuring method which enables a highly accurate measurement of concentrations of specific components in subjects of measurement even when the concentration measuring contact of a concentration measuring instrument is contaminated with drinks or the like. The concentration measuring instrument includes: a main body that has a concentration measuring contact 2, a light source 1 and a photodetector 6; and judging means 8 that calculates the difference between a non-contact-measured value, a value, measured by the photodetector 6 while keeping a subject of measurement out of contact with the concentration measuring contact 2, of the quantity of light that is emitted and entered by the light source 1 into the concentration measuring contact 2 and returned to the concentration measuring contact 2 and a predetermined reference value obtained in advance by making measurement while keeping the concentration measuring contact 2 clean and judges whether the calculation of the concentration of the specific component in the subject of measurement is effective or not by comparing the calculated difference with a predetermined threshold.