The control method of the agricultural nutrient solution supply device according to the present invention is to automatically supply the nutrient solution in the nutrient container to the crops in accordance with the type and time of the crop by storing the nutrient solution that automatically mixed the raw water and a number of fertilizer liquid in the nutrient container A feeder and a manual feeder connected to the nutrient container to manually supply the nutrient solution to the crop, wherein the manual feeder is connected to an automatic pump to the nutrient container, a hose is connected to the outlet of the automatic pump, and the hose is intermitted. A nutrient solution injection port having a valve is connected to the end of the hose, and the first filter for filtering the nutrient solution flowing out of the automatic pump between the outlet and the hose of the automatic pump is installed, the automatic feeder of the raw water supply pump A second filter is installed at an outlet, and a flow rate sensor for detecting a supply flow rate of raw water is installed at an outlet of the second filter to feed the raw water supply pump. Raw water conveyed by the second feeder is supplied to the nutrient solution tank through the second filter and the flow rate sensor, and a third filter is installed at the outlet of the nutrient solution supply pump for conveying the nutrient solution in the lower part of the nutrient solution container, and is formed in the third filter. The first return pipe is installed at one of the two branch outlets to return the nutrient solution conveyed by the nutrient solution supply pump to the nutrient solution bottle, and the plurality of fertilizer liquid transfer pipes respectively transferring a plurality of fertilizer liquids to the nutrient solution container. One or more return pipes are connected to the nutrient solution container, and the orifice and solenoid valve are respectively installed in a plurality of fertilizer liquid
