Abstract: An apparatus for isolating cell material from a tissue system and/or a liquid includes (1) a vessel open at the top, into which the cell material to be isolated can be introduced in the tissue system and/or the liquid; and (2) a separating device having a stamp-shaped configuration and including a flat separating disk having a peripheral edge fitting with the inner walls of the vessel in a fluid-tight manner and presenting at least one passage opening which is covered by a filter membrane, and which device can be inserted from the top into the vessel. The isolating disk pressurises the cell material inclusive of the tissue system and/or the liquid and acts thereupon with shearing forces by rotation. The cells and/or cell systems pass through the pores of the filter membrane whereas the residual tissue material is retained.