To provide a gear housing support structure capable of reducing the working noise of an electric power actuator to be transmitted to a vehicle body via a gear housing of a vehicular steering device, and enhancing the steering stability of a vehicle.

A gear housing 11 is installed to a vehicle body (a suspension member) via a support device having a bolt 31, a collar 33 and a rubber elastic body 36. A pair of flat parts 11a1 extending in the vertical direction and in the longitudinal direction of a vehicle and parallel to each other are formed in a fitting hole part 11a of the gear housing 11. In the circumference of the collar 33, a pair of right and left engagement projecting parts 33a passing through the rubber elastic body 36 and extending in the right-to-left direction of the vehicle, and engaged with the flat parts 11a1 of the gear housing 11 movably in the vertical direction and in the longitudinal direction of the vehicle, and non-movably in the right-to-left direction of the vehicle. A scooped portion 36a1 as a rigidity-reducing means for reducing the rigidity in the vertical direction of the vehicle is provided above and below the rubber elastic body 36.