A device for expressing human breast milk has a breast shield for bearing against a mother's breast, a vacuum pump for generating a vacuum, a line which connects the vacuum pump to the breast shield and is intended for transmitting the vacuum generated to the breast shield, and a chamber. The line ends on the pump side in a first port of the chamber. The chamber has a second port for connection to a milk collecting container. The two ports in the chamber are connected to each other in terms of fluid communication. During the expressing operation, the line forms a milk line for transporting breast milk expressed in the breast shield to the chamber and from the chamber to the milk collecting container. The pump can be designed to be quiet and small.