The present invention provides an expandable infiltration plant that can be used as a stormwater storage facility, capable of reducing nonpoint pollutants contained in rainwater, and capable of continuously supplying water required for vegetation growth. According to a preferred embodiment of the present invention, an expanding type infiltration plant facility capable of vegetation growth by retention and evaporation by infiltration of rainwater infiltrates into a space between a catchment installed with an inflow port at one side and a drainage installed with an outflow port at the other side An outer wall constructed so as to confine the rainwater infiltrated around the filtration space formed by performing the depressurization to a certain depth under the ground； A water supply pipe installed at a lower portion of the filtration space to supply water to the vegetation layer； A filtration layer filled with gravel or a filter medium in the filtration space at a predetermined height above the water supply pipe； A vegetation layer filled with gravel to fill various plants, the vegetation layer being filled with the gravel on the upper part of the filtration layer and having a top surface formed lower than the inlet； The water supply pipe includes a plurality of bottom side supply pipes arranged on the bottom side of the filtration space, and a plurality of water supply pipes connected to the bottom side of the bottom side supply pipe and extending upward to the surface of the vegetation layer or the vegetation layer. Wherein the vertical supply pipe and the vertical supply pipe each have an evaporation hole distributed through the thickness thereof and a pipe cap at an end thereof； An inner pipe is installed inside the vertical supply pipe and a spiral wing is further provided between the inner pipe and the vertical supply pipe to increase the flow velocity of the intrusion rainwater.본 발명은 빗물의 저류 시설로 사용이 가능하고 빗물에 포함된 비점오염물질의 저감이 가능하며 식생 성장에 필요한 수분의 지속적인 공급이 가능하도록 한 확
