The purpose of the present invention is to establish a novel therapy method for hyperbilirubinemia and therefore, to provide a bilirubin excretion enhancer. The present invention provides a bilirubin excretion enhancer comprising, as an active ingredient, a serum albumin domain II-like protein comprising a serum albumin subdomain IIA. In one embodiment, the serum albumin subdomain IIA has an amino acid sequence of SEQ ID NO: 1. in one embodiment, the serum albumin domain II-like protein is a serum albumin domain II. In one embodiment, the serum albumin domain II comprises the amino acid sequence of SEQ ID NO: 4.
