The invention discloses a leakage measuring instrument, which comprises a leakage collecting component, a supporting component, a collection protecting component, a drainage component and a leakage measuring component. The leakage measuring instrument is characterized by also comprising a filtering component. The supporting component is arranged at the bottom of the collection protecting component; and the leakage collecting component, the filtering component and the drainage component are arranged in the collection protecting component, wherein the drainage component and the leakage collecting component are combined together, and the leakage measuring component measures the water drained by the drainage component. The leakage measuring instrument has the advantages of small volume, low cost, convenient installation and portability; and the measuring method is simple and has high precision. The leakage measuring instrument can be directly arranged at a certain depth of any position of the farmland, and realize timely, quantitative and intuitional automatic measurement of leaked water in a deep layer.