PURPOSE: To make small the gear sound of counter gears to transmit motive power to the speed shift main shaft of a transmission from the PTO shaft of an engine and prevent the increase of gear width, in the case of a walking rice planting machine.

CONSTITUTION: A synthetic resin rear 27b is made to mesh with the gear 25 of the PTO shaft 23 of an engine 2, and a hard steel gear 27a is made to mesh with the gear 29 of the speed shift main shaft 24 of a transmission, and the gear 27b is integrally coupled to the gear 27a, and the gear 27a to form the shaft-support portion of the tip of a shaft 26 is made to fit to the tip portion of the shaft 26 of a hydraulic pump 71. Thus, the gear 27b is rotated by meshing with the gear 25 at a high peripheral speed, and the gear 27a is rotated by meshing with the gear 29 at a low peripheral speed and high torque.