A hybrid driving unit (7) in which a second electric motor (23) is disposed on the side closer to the front of a vehicle (the side closer to an internal combustion engine (5)) than a first electric motor (20). A casing member (14) is formed such that an inner diameter of a part thereof, in which a stator (28) of the second electric motor (23) is fixed, is larger than that of a part in which a stator of the first electric motor (20) is fixed. This allows the second electric motor (23) to be constructed so as to have a large radial dimension and, to that extent, allows the length thereof in the longitudinal direction to be suppressed. Accordingly, this allows the length of the whole hybrid driving unit (7) to be shortened.