Abstract: The invention relates to a differential polarizing laser-scanning microscope (DP LSM) for determining differential polarization quantities of a material, comprising a laser light source (L) for scanning the sample and illuminating it with a coherent and monochromatic light, a microscope unit (ME) with a sample holder for providing a preselected optical magnification and imaging and a polarization state setting unit (PAA) positioned in the illuminating beam path (between the light source and the sample holder). The microscope is further provided with detectors (D1, D2) in the observing beam path, at least one filter holder in front of the detectors and a signal-processing unit (VE) for processing the electrical signals of the detectors. In the DP-LSM microscope an optical element (DP) is located in the common beam path comprising the illuminating and the observing beams, for separating the orthogonal polarization components.