A laser gas analyzer includes a wavelength-variable laser having a wide wavelength-variable width, a light-split module configured to split an output light of the wavelength-variable laser into a measurement light and a reference light, a first gas cell into which gases to be measured are introduced, and the measurement light is made to be incident, and a data processor configured to obtain an absorption spectrum of each of the gases to be measured based on a reference signal related to the reference light and an absorption signal related to an output light of the first gas cell, and to obtain concentrations of the respective gases to be measured.