Abstract: Device for transferring an invalid from his invalid chair to a motor vehicle, and conversely, while staying on his seat, wherein the seat of the invalid chair is removably mounted on an undercarriage having two bearing back-wheels and two steering front wheels. The motor vehicle has a pair of arms which are extensible towards the outside and retractable inside of the vehicle and are also vertically movable. The arms fit into female slippers on the removable seat to effect the transfer of the seat to the vehicle.