An X-ray multichannel spectrometer comprising a polychromatic source (2), a holding means (3) for holding a sample (1), a fluorescence channel (4) that selects X-ray beams of a special wavelength and energy, and a detector (5) for measuring the selected X-ray beams, a diffractometry channel (6) that selects, by means of a monochromator (7), an X-ray beam wavelength of the source subsequent to diffraction of the X-ray beams by the sample, and a detector (8) for measuring the selected X-ray beams, is characterized in that a single slit device (9) is provided between the source and the sample, which can be moved transversely with respect to the direction of the beam from the source, and the monochromator of the diffractometry channel is stationarily disposed with respect to the source and the sample and has an entry single slit (10) which defines, together with the movable single slit device and the sample position, the characteristic diffraction angle 2θ of a predetermined crystal structure of the polycrystalline sample at the wavelength of the source selected by the monochromator. In this fashion, reliable element analysis and inexpensive X-ray diffraction can be performed with the same device, wherein the at least three collimator arrangements that have been necessary up to now for the diffractometry channel, are omitted and the monochromator does not require any complex diffraction mechanism in the diffractometry channel.