To provide a chemical spray control device for a sulky control machine, giving consideration to the response delay of a pressure sensor due to opening and closing of a flow control valve.

In the constitution of the chemical spray control device for a sulky control machine, spraying chemical solution from a nozzle boom 24 to which the solution is supplied from a protection tank 19 filled with the chemical solution through a protection pump 14, while controlling the spray rate by the opening and closing of a flow control valve 30 set in a spraying circuit, when the difference between a targeted spray rate and an actual rate becomes less than a prescribed valve, the opening and closing of the flow control valve 30 is once stopped and resumed after the fluid pressure fluctuation of the spraying circuit has subsided.