Abstract: A concentration measuring device according to an embodiment may include a light-emitting unit configured to generate measurement light, a measurement unit configured to receive first measurement light that is part of the measurement light and that passes through a sample that is a measurement target, and a reference measurement unit configured to receive second measurement light that is part of the measurement light and that does not pass through the sample, wherein the concentration measuring device may be configured to measure a concentration of a chemical material in the sample by measuring an amount of light absorbed by the sample based on an amount of light detected by the measurement unit and an amount of light detected by the reference measurement unit.