The absorption analyzer of the type provided with light sources (3a, 3b), cells (1, 2) containing a reference gas and an ingredient gas to be measured, respectively and a detector (5) for determining the absorption of the light emanating from the light sources and passing through the cells, is additonally equipped with a gas filter (8) arranged in the optical path between said light sources and the detector and contains an ingredient gas with an absorption spectrum band that nearly corresponds to that of an ingredient gas to be measured or an ingredient to be measured. The advantage of the invention is that a relatively large range of concentrations of gas ingredients can be measured with the same type of cells having the same cell length.