A temperature responsive sheet is disclosed that comprises a chemically modified water-soluble elastin obtained by N-acylating at least some of the primary amines and secondary amines contained in a high molecular weight water-soluble elastin molecule and coupling some or all of carboxyl groups contained in the molecule with a glycine alkyl ester. Also is disclosed a process for producing a cell sheet that comprises preparing above the temperature responsive sheet a film that functions as a scaffold for animal cells, culturing specific cells on the film so as to prepare a cell sheet, and subsequently separating the cell sheet and the temperature responsive sheet comprising the chemically modified water-soluble elastin under conditions of no greater than the culturing temperature for the cells.