The present disclosure relates to a synthetic leather including a base material layer containing a fiber base material, in which at least a part of the synthetic leather contains a polypeptide derivative, the polypeptide derivative contains a block copolymer containing a first segment containing a polypeptide skeleton, and one or a plurality of second segments that are bonded to the first segment, the polypeptide skeleton is a recombinant polypeptide skeleton or a hydrophobic polypeptide skeleton, and the second segment contains a molecular group having a plasticizing function for the polypeptide skeleton.