Auxiliary drive device for a wheelchair, comprising: at least one electrically driven drive wheel and a coupling mechanism for coupling the auxiliary drive device to a wheelchair, wherein the coupling mechanism includes a locking element which is movably supported in the coupling mechanism, wherein the movable locking element can be in a locking position in which it causes locking in a positive-locking manner so that the auxiliary drive device is coupled to the wheelchair and the locking element, by operation of a handle, can be moved in a release position in which uncoupling of the auxiliary drive device from the wheelchair is possible, wherein the locking element is designed such that, in a spring loaded manner, it can close a coupling groove completely or at least partially and that in the process of coupling it contacts in a spring loaded manner an element to be held in a positive-locking manner for effecting the coupling, characterized in that the coupling groove is arranged, with respect to the handle such that, when the auxiliary drive device is held by means of the handle, the coupling process is carried out by lowering the auxiliary drive device, wherein the element to be held in a positive-locking manner for effecting the coupling comprises a coupling pin and enters, due to the lowering, into the coupling groove and the coupling process is completed when the coupling pin to be held in a positive-locking manner for effecting the coupling has come in abutment with a corresponding bottom of the coupling groove and wherein the coupling pin and the coupling groove are designed such that in case of a coupling of the auxiliary drive device with the wheelchair safe to operate a tilting of the wheelchair is possible. at least one electrically driven drive wheel and a coupling mechanism for coupling the auxiliary drive device to a wheelchair, wherein the coupling mechanism includes a locking element which is movably supported in the coupling mechanism, wherein the movable locking element can be in a locking position in which it causes locking in a positive-locking manner so that the auxiliary drive device is coupled to the wheelchair and the locking element, by operation of a handle, can be moved in a release position in which uncoupling of the auxiliary drive device from the wheelchair is possible, wherein the locking element is designed such that, in a spring loaded manner, it can close a coupling groove completely or at least partially and that in the process of coupling it contacts in a spring loaded manner an element to be held in a positive-locking manner for effecting the coupling, characterized in that the coupling groove is arranged, with respect to the handle such that, when the auxiliary drive device is held by means of the handle, the coupling process is carried out by lowering the auxiliary drive device, wherein the element to be held in a positive-locking manner for effecting the coupling comprises a coupling pin and enters, due to the lowering, into the coupling groove and the coupling process is completed when the coupling pin to be held in a positive-locking manner for effecting the coupling has come in abutment with a corresponding bottom of the coupling groove and wherein the coupling pin and the coupling groove are designed such that in case of a coupling of the auxiliary drive device with the wheelchair safe to operate a tilting of the wheelchair is possible.