To provide a soil improvement structure that prevents differential settlement and that is effective as a soft ground countermeasure or a liquefaction countermeasure, and a soil improvement method.

A soil improvement structure comprises a pile 11 that is borne by a bearing stratum 30 of object ground, and a drain section 12 that is made of crushed stones 18 and formed over a position deeper than a groundwater level 31 of the object ground along an outer peripheral surface of the pile 11. Constitution like this makes a structure supported by the pile 11, makes consolidation settlement promoted by shortening a drainage distance by the drain section 12, and makes excess pore water pressure dissipated by the drain section 12. Thus, the soil improvement structure prevents differential settlement, and effectively serves as a soft ground countermeasure or a liquefaction countermeasure.