An apparatus (1) for extracting milk from a breast, comprising means (2,3) for receiving at least a portion of a breast and its nipple a container (5) for collecting the milk operatively connected to said means (2,3) for receiving at least partially a breast and its nipple a pump unit (100) operatively connected to said means (2,3) for receiving at least partially a breast and its nipple, said pump unit (100) being operated manually to generate at least an aspiration able to cause a suction on the breast by imposing a predetermined degree of vacuum within said means for receiving the breast and the nipple. The manually operated pump unit (100) comprises means for regulating the degree of vacuum that is generated. Pump unit (100) operated manually and connectable to a kit for collecting milk from a breast.