A new method and a new type of measuring-microchamber for the investigation of cellular dielectrophoresis is presented. The method is based on the observation of the trajectory of a single cell in gravitational and electric fields being crossed and orientated perpendicularly to the observation direction. By means of this method the whole dielectrophoretic spectrum ranging from negative to positive dielectrophoresis may be easily and quickly obtained. The experiments carried out on different cell types showed that the dielectrophoretic spectra, as well as the dependence of the critical frequency upon medium conductivity and cell size agree well with the predictions of a new model of the dielectrophoretic mechanism proposed by Sauer.