The invention relates to a breast shield unit for use together with a breast pump for expressing human breast milk, comprising a breast shield (2) for receiving a mothers breast (B) and a media separating device (7, 9) for exerting a vacuum in the interior of the breast shield (2). Said breast shield (2) has a receiving area (33) for receiving a nipple of the mothers breast (B). The media separating device (7, 9) has a media separating diaphragm (9) which can be moved to and fro between two positions for the purpose of transmitting the vacuum. The media separating diaphragm (9) is located in the receiving area (33), at least in one of the two aforementioned positions. The breast shield unit according to the invention can be produced extremely compactly, despite integrated media separation, and minimizes the dead volume.
