An engine-and-electric-machine assembly, including an engine (8) and an electric machine (9). The crankshaft (7) of the engine has an extension section (7-3) that extends to the exterior of the engine, and the rotor (3) of the electric machine is mounted to the extension section. The present disclosure improves the integration level of the engine-and-electric-machine assembly, and reduces the weight and volume of the engine-and-electric-machine assembly. A vehicle driving device including the engine-and-electric-machine assembly is also disclosed.