The objective of the present invention is to provide a light absorbency measuring device and a light absorbency measuring method with which the light absorbency of a component being examined can be measured easily using a microchip.The light absorbency measuring device of the present invention is characterized by being provided with: a microchip provided with a first flow path through which a liquid specimen flows, a second flow path which communicates with the first flow path and which separates a component being examined from the liquid specimen, and a measuring portion into which the component being examined, separated from the liquid specimen by the second flow path, flows； a light source which radiates light in a prescribed wavelength region； an optical mechanism for irradiating the microchip with radiated light from the light source； an image capturing element having as an imaging field of view a region that includes the measuring portion of the microchip； and an image processing mechanism which has the function of subjecting image data relating to an image captured by the image capturing element to image processing to identify the measuring portion within the image, and the function of calculating the light absorbency of the component being examined, in the measuring portion.L'objet de la présente invention est de fournir un dispositif de mesure du pouvoir d'absorption de la lumière et un procédé de mesure du pouvoir d'absorption de la lumière avec lesquels le pouvoir d'absorption de la lumière d'un composant en cours d'examen peut être mesurée facilement à l'aide d'une micropuce. Le dispositif de mesure du pouvoir d'absorption de la lumière selon la présente invention est caractérisé en ce qu'il est pourvu : d'une micropuce comprenant un premier trajet d'écoulement à travers lequel un échantillon liquide s'écoule, un second trajet d'écoulement qui communique avec le premier trajet d'écoulement et qui sépare un composant en cours d'examen par rapport à l'éc
