Automatic irrigation device

The utility model relates to an automatic irrigation device which comprises a water tank and a water injection pipe, at least one water delivery pipe is fixed at the same height position of the periphery of the water tank, a plurality of three-way pipes are fixed on each delivery pipe, an irrigation pipe is fixed at a bottom outlet of each three-way pipe, a potted plant is arranged below each irrigation pipe, and an adjusting pipe is sleeved on the lower portion of each irrigation pipe. A conical sealing face is arranged in an inner hole in the lower portion of the adjusting pipe, a floating ball is arranged below the sealing face, a limiting net plate is fixed to the bottom of the adjusting pipe, a sealing groove is formed in the inner wall of the upper portion of the adjusting pipe, a sealing ring is arranged in the sealing groove, and a locking device for locking the adjusting pipe is arranged on the water filling pipe. When the liquid level in the potted plant drops below the required position, the floati