The invention relates to an automatic quantifying water supply device which comprises a quantifying device 1, a stirring device 2, a water filling device 3, a draining device 4 and an automatic control device 5. The automatic quantifying water supply device is characterized in that the quantifying device 1 comprises a water storage bucket 1-1 and a lower bound contact 1-12. An upper bound contact 1-8 is fixed at the lower end of a lifting lead screw 1-7, a neutral contact 1-10 is fixed at the lower end of a neutral current conducting rod 1-9, and the lower bound contact is fixed at the lower end of a lower bound current conducting rod 1-11. The lifting lead screw 1-7, the neutral current conducting rod 1-9, the lower bound current conducting rod 1-11, the upper bound contact 1-8, the neutral contact 1-10 and the lower bound contact 1-12 are respectively arranged in the water storage bucket 1-1 which is arranged below a bucket cover 1-2 to form a liquid level control mechanism together. The automatic quantifying water supply device has the advantages of being high in automation, accurate in quantifying control, convenient to adjust in a quantifying mode, and suitable for industrial producing, capable of saving producing cost, improving product quality, reducing labor intensity, and being stable and reliable in performance.