A spectroscopic analyzer according to an embodiment includes: a Fabry-Perot QCL element configured to emit a laser light including a plurality of mode lights respectively corresponding to a plurality of modes indicating a discrete oscillation spectrum; a diffraction grating configured to disperse the laser light emitted from the QCL element into the plurality of mode lights; and a light detector configured to detect the mode light dispersed by the diffraction grating and then transmitted through a sample.