To stabilize an oxidation-reduction state of soil suitable for growth of a plant.SOLUTION: A sprinkling water supply device 100 comprises a body part 50 having an inflow part 10 for making water flow in and an outflow part 30 for making the water flow out and filters 20a and 20b stored in the body part 50 and being 50 μm-1000 μm in filtration accuracy, and the filter 20a and the filter 20b are arranged in an upper position than the outflow part 30, and in a stopping state of stopping an inflow of water from the inflow part 10 and an outflow of water from the outflow part 30, the filter 20a and the filter 20b are positioned upward above a water level position of the water staying in the body part 50, and the whole of the filter 20a and at least a part or more of the filter 20b are exposed without soaking the whole of the filter 20a and the whole of the filter 20b in the water staying in the body part 50.SELECTED DRAWING: Figure 2【課題】植物の生育に好適な土壌の酸化還元状態の安定化を図ること。【解決手段】灌水供給装置１００は、水が流入される流入部１０及び水が流出する流出部３０を有する本体部５０と、前記本体部５０に収容され、濾過精度が５０μｍ～１０００μｍのフィルタ２０ａ，２０ｂを具備し、フィルタ２０ａ及びフィルタ２０ｂが流出部３０より上位位置に配設し、流入部１０からの水の流入及び流出部３０からの水の流出が停止している停止状態で、本体部５０内に滞留している水の水位位置より上にフィルタ２０ａ及びフィルタ２０ｂが上に位置し、本体部５０内に滞留している水にフィルタ２０ａの全体及びフィルタ２０ｂの全体を浸漬させることなくフィルタ２０ａの全体及びフィルタ２０ｂの少なくとも一部以上を露出させているものである。【選択図】図２
