PROBLEM TO BE SOLVED: To provide an automatic watering configuration capable of suppressing excess or shortage of water amount in soil in consideration of soil properties in a field.SOLUTION: A automatic watering system comprises a water content measuring device 20, a water supply device 30, a watering amount determination part 11, and a control device 14. The water content measuring device 20 measures water content of soil in a field. The water supply device 30 irrigates the field. The watering amount determination part 11 obtains the water content measured by the water content measuring device 20 just before the water supply device 30 irrigates the field, and determines the appropriate water amount for watering during a unit period based on the water content. The control device 14 controls the water supply device 30 so as to perform watering of the water amount determined by the watering amount determination part 11 to the field. The watering amount determination part 11 includes a conversion table 112 in which the water contents according to soil quality in the field and the appropriate water amounts for watering during the unit period are associated with each other, and determines the water amount by checking the water content measured by the water content measuring device 20 against the conversion table 112.
