Cutter unit equipped with a pump (4) which cutter unit comprises a rotatable cutting device (1) with the help of which underwater soil can be cut wherein the mass that becomes created during the cutting, such as the mass that becomes created from the soil and water moves inside the cutting device (1) and further to the pump (4) with the help of which pump the mentioned mass being in a fluid form is pumped to a suitable location. A cutting/crushing device (2, 8) is adjusted between the cutting device (1) and the pump (4) which cutting/crushing device comprises counter blades (8) and a rotating, double- ended knife edge (2) installed at the front side of these seen from the flow direction of the mass which knife edge is installed in an eccentric way in relation to its axis of rotation.