The purpose is to select low-molecular-weight compounds which are effective in inducing differentiation of mesenchymal stem cell into hepatocyte and to develop a safe differentiation-inducing method having excellent efficiency of differentiating mesenchymal stem cell into hepatocyte. Provided are at least one compound selected from the group consisting of compounds represented by formulae (1) and (2), a salt thereof, or a solvate of them; a differentiation inducer comprising at least one compound selected from the group consisting of compounds represented by formulae (1) and (2), a salt thereof, or a solvate of them; and a differentiation inducer comprising a compound represented by formula (8), a salt thereof, or a solvate of them.