Detailed is a device for cleaning an immersed surface including a body and members for driving the body over the immersed surface in a main direction of advance; a filtration chamber which is provided in the body and which has: a liquid inlet conduit which extends inside the body and which has a lower end which forms a liquid inlet and an opposing upper end which opens into a filtering device; a liquid outlet out of the body; a hydraulic circuit for the flow of liquid between the inlet and the liquid outlet through the filtering device, wherein the inlet conduit has a regular cross-section whose surface-area varies from the lower end thereof up to a maximum value at the upper end thereof which opens in the filtering device.