The present invention provides a flexible, biocompatible transparent sheet (8) which has high biocompatibility and a high ability to adsorb a biologically relevant substance, which can be used as a novel biomaterial, and which can be used to observe the propagation, differentiation, and/or the like of living cells in real time. The biocompatible transparent sheet (8) is produced in such a manner that a biocompatible ceramic film (2) is formed on a substrate (1) soluble in a solvent (11) incapable of dissolving biocompatible ceramics by using exemplary a laser ablation process, the substrate (1) depositing the film (2) is dipped in the solvent (11) and dissolved off, and the isolated film (2) is then dried. The biocompatible transparent sheet (8) is utilizable of producing a flexible cultured cell sheet which can be directly transplanted to an affected area. The cell sheet can be prepared in such a manner that cells are seeded on the biocompatible transparent sheet (8) and then propagated.