A substrate for feeding cells and/or tissues which is composed of a porous body having a thin film surface and a porous surface and which can be used in the regenerative medical techniques. A cell/tissue feeder is produced by cultivating tissues on the porous surface of the porous body. Cells are seeded on the porous surface of the body, followed by the cultivation of the cells to thus form and/or regenerate tissues. An aqueous solution of silk proteins, to which a water-soluble organic solvent is added, is introduced into a mold whose bottom or top surface is surface-roughened, followed by freezing the aqueous solution and then thawing the frozen aqueous solution to form a porous body having a thin film surface and a porous surface.