The present invention provides a base material for forming a connective tissue structure which can accurately cut the connective tissue structure to a predetermined shape and a method for producing the connective tissue structure. A cutting-line forming groove (28) is formed in a surface of a base material (19). The base material (19) is placed under an environment in which a biological tissue material is present. A membranous connective tissue structure (20) is formed on the surface of the base material (19). At that time, a connective tissue (30) is made to invade into the cutting-line forming groove (28). A cutting line (31) for cutting is formed in the connective tissue structure (20). The connective tissue structure (20) is accurately cut along the cutting line (31) to a predetermined shape.
