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. <EOS>