PURPOSE: To improve the maneuverability of a machine body in a cultivator and the like by constructing a transmission case with an engine loaded above and a wheel axle pivotted below to be doglegged for positioning the wheel axle at the center of gravity of the machine main body.

CONSTITUTION: A transmission case 6 is constructed to be almost doglegged in the side with an engine 2 loaded on its upper side 6a, a wheel axle 4 pivotted on the lower end of its slant side 6b, and a handle 3 fixed in its bent part 6c. It is designed to position the center of gravity of a machine main body 1 at the center of the wheel axle 4 and keep the slant side 6b and the handle 3 on a straight line. This construction permits to operate the machine main body 1 lightly by the handle 3.