The present invention relates to a technique for analyzing the concentration of a specific component in a sample liquid, such as a method for analyzing a sample. The analyzing method includes a first detection step for irradiating light from a light source (50) onto a reaction system to detect a response from the reaction system (56) as a first detection result. The reaction system contains a sample liquid and a reagent. The method also includes a second detection step for irradiating light onto a reference board (54) to detect a response from the reference board as a second detection result. The response from the reference board under light irradiation is dependent on wavelength. The method further includes a calculation step for calculating the concentration of the specific component in the sample liquid based on the first and second detection results.