The present invention is a method and an apparatus for examination/diagnosis of lifestyle related disease, wherein the test sample from a human or other animal subject is irradiated with light having a wavelength region of a region of 400 nm-2,500 nm or a part of the region, of which the reflection light, the transmission light, or the transmission reflection light is then detected to give spectroscopic data of absorbance, and afterward a previously prepared analysis model is used to execute an analysis of the absorbance at the whole or specific wavelength used for the measurement.