To improve the longitudinal balance of the gravity center of a sulky rice transplanter.

This transmission case arranging structure of a sulky rice transplanter is obtained by disposing a transmission case 5 below an engine 2, disposing a fuel tank above the engine 2, covering the engine 2 and the fuel tank with a hood, forming the front wall of the hood in an about quarter circular shape which is forward and downward inclined and forward swollen on the side view, and disposing an engine pulley disposed on the side of the engine above a casing body also used as a step, disposing a transmission pulley disposed on the side of the transmission case 5 below the casing body, and winding a transmission belt over both the pulleys to interlock and connect both the pulleys each other.