To provide a foundation assembly which can be constructed easily by absorbing positional displacement between a supported object and a foundation structure in three axial directions and mounting a pole or the like of the supported object without performing machining such as cutting, and a finished structure employing the same.

The foundation assembly comprises a foundation structure 10 penetrated with two or more through holes 12, and a plurality of piles 20 which are inserted into the through holes of the foundation structure, respectively, and driven into the ground. The foundation structure includes a connection member 30 which is provided in a central part 11 and to which a supported object 40 is mounted. The foundation assembly is configured to absorb positional displacement between the supported object and the foundation structure in a height direction and positional displacement within a plane orthogonal to the height direction by means of an adjustment function of the connection member. The finished structure employing the foundation assembly is also provided.