In a chromatography quantitative measuring apparatus according to the present invention, a beam applied from a light source to a chromatography test strip is formed into an elliptical shape by an optical means such as a cylindrical lens, a variation in absorbance that accompanies elution of a marker regent is detected while the elliptical beam is applied between a marker reagent hold part and a detection part, and a measurement is automatically started in a prescribed period of time since the detection of variation. According to the chromatography quantitative measuring apparatus so configured, non-uniform coloration is reduced by shaping the beam elliptically with the optical means, whereby the accuracy of quantitative analysis is enhanced, and the apparatus can be operated easily.