PROBLEM TO BE SOLVED: To provide a spraying amount controller that can execute spray control using vehicle speed signals in different forms to a traveling machine body such as a tractor which outputs these vehicle speed signals.SOLUTION: A spray controller 4 of a traveling type liquid spraying machine 1 comprises: spray state detection means 10 that detects a spray state an adjustment section 20 that adjusts the spray state and a control section 5 that receives inputs of a vehicle speed signal output from the traveling machine body and of a detection signal from the spray state detection means 10, compares a set target spray condition with an actual spray condition obtained by applying arithmetic processing to the vehicle speed signal and the detection signal, and outputs a control signal to the adjustment section 20. The control section 5 has a vehicle speed conversion factor with respect to each type of the vehicle speed signal, selects a vehicle speed conversion factor corresponding to the input vehicle speed signal, obtains an actual vehicle speed value from the vehicle speed signal and uses the actual vehicle speed value to obtain the actual spray condition.
