PURPOSE: To restrain elastic vibration by constructing a support bracket to support a power unit to be mounted on both of a transmission and an engine for improving the connecting rigidity between the engine and the transmission.

CONSTITUTION: The first fitting part 20a on the rear end of a bracket 20 to support a power unit 1 and the second fitting part 20b at the top of a double- staged projection extended to avoid an oil pan 2b at the upper end are respectively provided. The fitting part 20a is mounted on the side end 3a of a transmission 3 via a bolt 21, while the fitting part 20b is mounted to the underside of a flange part 2c of a cylinder block 2a via a fixing member 22. In this construction, the bracket 20 functions also as a gazette, and increases the connecting rigidity between the engine 2 and the transmission 3.