Auxiliary drive and automobile equipped with the same

There are included a first motor-generator (2); speed change device (104) disposed between an engine (101) and a first wheel drive shaft (105); demanded braking force detection device (21) for detecting braking force demanded by the driver; engine braking force calculation device (22) for calculating engine braking force; and regenerative braking force calculation device (23) for calculating regenerative braking force resulted by regenerative power generation of the first motor-generator (2). Gear ratio or shift points of the speed change device (104) is controlled on the basis of information from the demanded braking force detection device (21), the engine braking force calculation device (22) and the regenerative braking force calculation device (23).