To solve the problems of uneven traveling because of the availability of only two kinds of gear reductions when driven by an engine and of the requirement of a specially designed transmission in completing a hybrid vehicle by providing a first motor, a clutch (a second clutch), a second motor and a specially designed transmission inside the conventional automotive transmission casing.

A parallel hybrid vehicle is realized by installing a first rotating machine 8, a clutch 9, a second rotating machine 10 inside a clutch housing 2 making use of the conventional engine vehicle body as it is and, in addition, by providing a battery 5 and an inverter 4. Because the vehicle body does not need to be newly designed, production cost can be reduced. As a transmission 3, the conventional one used in the engine vehicle is used as it is so that the same multiple-step gear reductions as in the conventional art can be achieved and smooth traveling is obtainable when applied to large vehicles.