The particle porosity and bed porosity of fine powders with the range of the grain size 0-100 mu m have been investigated. The densymetric measurements were used during the research. Obtained values of apparent density of micrometric fine materials were compared to apparent densities of the same type of material samples but with the range of the grain size 40-315 mu m. Using of the comparative method to measure of the apparent density of micrometric fine materials makes possible the calculation of particle porosity as well as bed porosity.