The present invention provides a prosthetic tissue or sheet capable of withstanding implantation operations, which can be used in actual operation and can be produced by culture. The present invention also provides a novel therapy which can substitute for cell therapy. Particularly, the present invention provides a method for producing a prosthetic tissue comprising a cell derived from a part other than myocardium and capable of withstanding implantation operation. The above-described objects of the present invention were partially achieved by finding that by culturing cells under specific culture conditions, the cells are unexpectedly organized into a tissue, and the resultant prosthetic tissue is capable of being detached from culture dishes. The present invention also provides a three-dimensional structure applicable to heart, comprising a cell derived from a part other than the myocardium of an adult.