Abstract: An apparatus for applying at least one teat cup (1) to a teat (2) of an animal (3), which includes a sensor arrangement (5) which has at least one sensor unit (6) that can be brought into contact with a rear body part of the animal (3). To apply a teat cup, an application device (14) is provided, which comprises at least one positioning arm (15) for applying the at least one teat cup (1) to the teat (2) of the animal (3). The application device is coupled with a controller, which connects to a positioning device. The sensor arrangement (5) comprises a measuring device (9) connected to the sensor unit (6). The sensor arrangement (5) is stationarily arranged with respect to a reference position. The sensor unit (6) is designed and constructed such that it follows the movement of the animal (3), and the measuring device (9) measures the change of position of the sensor unit (6) with respect to the reference position.