Abstract: The invention relates to an apparatus for carrying out spectral analysis which is provided with diffraction grating means (1-6, 12-15) for dispersing the incident radiation (3). In order to achieve a high spectral resolution in an economically advantageous manner, the diffraction grating means comprises a plurality of grating surfaces (1-6, 12-15) which are arranged so that the radiation (3), after diffraction from the first grating surface (1, 12), is subject to diffraction also in the other grating surfaces (2-6, 13-15). The grating surfaces hereby have such an orientation that the wavelength dispersion at diffraction from one grating surface acts to increase the wavelength dispersion at diffraction from the following grating surfaces.