Disclosed is a device for loosening bones such as ribs from a meat piece from slaughtered animals such as pigs. The bone puller such as rib puller can be hand-held and e.g. pneumatic activated or connected to a robot, and is much easier to use than prior art pneumatic rib pullers and also impose less working stress upon the user. The bone puller may comprise a counter hold for supporting the device towards a belly piece from a slaughtered animal, a string for loosening a bone, a movable pull bar for pulling the string, and a holding-down bar for holding down a bone while loosening this bone. The device may further comprise loading means located at the end of the holding-down bar such that the string can surround the loading means and where this loading means secure feeding of the string around an exposed bone end before loosening this bone.