When a sprayer spreads pesticides in the field, the operator on board is exposed to the mist of pesticides. The automatic operation without operator on board could certainly alleviate such a shortcoming. A joint research team organized by NARC and Mitsubishi Farm Machinery Co. Ltd. Developed and tested an automatic operation method by the light tractor “Paddy vehicle” with a sprayer. The operation system included a straight line automatic operation which followed the rows of rice plants and a turning action supported by a remote controller handled by the operator. The paddy vehicle equipped with a boom sprayer could carry out automatic spraying operations without an operator on board in the paddy fields. The automatic forward movement of the vehicle following the straight row of rice plants, the automatic turning by the computerized program, and the maneuver remotely controlled by the operator on the road for the accurate position ready for the next stroke were tested. The operation of the paddy vehicle was found to be successful as had been intended from the design stage. This new automatic operation system enables 1 operator to handle 2 or more paddy vehicles simultaneously in paddy fields.