An analyzer analyzes a sample based on optical characteristics of the sample. The analyzer includes a measuring unit that measures absorbances of two or more wavelength identifying samples having different concentrations and having absorbance characteristics in which there is no extremum in a wavelength band including a wavelength to be identified, the wavelength identifying samples being made of a same material; a calculator that obtains a gradient of a straight line indicating a relationship between the concentrations and the absorbances of the identifying samples measured by the measuring unit; and an identifier that identifies an actual wavelength of light to be measured by the measuring unit, based on a degree of coincidence between the gradient of the straight line calculated by the calculator and at least one pre-obtained reference gradient of a straight line indicating a relationship between concentrations and absorbances of reference samples made of the same material as the wavelength identifying samples for at least one wavelength.