An object of the present invention is to provide a non-human model animal rich in stromal tissue, a cell structure useful for producing the above-described non-human model animal, a method for evaluating a test substance in which the above-described non-human model animal is used, and a method for producing the above-described non-human model animal. According to the present invention, a cell structure is provided which contains a biocompatible macromolecular block and at least a cancer cell and a mesenchymal cell, and in which a plurality of the above-described biocompatible macromolecular blocks are arranged in gaps between a plurality of the above-described cells.
