PURPOSE: To reduce a differential gear noise by suppressing the vibration transmitted to a car body side and provide differential gear mounting structure for reducing the displacement quantity, which is caused by the vibration of a differential gear and an engine.

CONSTITUTION: The third differential gear mount 9, one of three differential mounts 7 to 9 for connecting a front differential gear 3 on a car body side 10, is mounted on an engine 1, and a spring constant to the car body side 10 is set small so as to reduce the vibration or differential gear noise transmitted to the car body side 10. The third differential gear mount 9 is installed at a place where the torque of the engine 1 itself caused by the output of the engine 1 and the torque of the differential gear 3 itself caused by the input to the differential gear 3 are canceled each other so as to reduce their displacement quantities to the car body side 10.