A milk sucking pump having a top component with a breast joining piece and which is or can be detachably fixed to the opening of a container and a hand pump unit that is detachably connected thereto by a connecting branch or a connecting bore. The hand pump unit has a cap-like connection section and a pump piston which can be moved to and from in a piston-swept volume by a rotatable actuating handle that has a return mechanism. This invention provides a simple construction and good handling. The cap-like connection section and the piston-swept volume are combined to form a uniform cap component which is fixed to the top component. The return mechanism acts upon the actuating lever and is mounted on the cap component.