PROBLEM TO BE SOLVED: To provide osteogenesis promoting agent which effectively promotes osteogenesis.SOLUTION: The osteogenesis promoting agent according to one embodiment of the present invention includes one or more selected from the group consisting of the ligand and agonist of GPR81 and precursors thereof as active ingredients. The ligand may be one or more selected from the group consisting of lactic acid, α-hydroxybutyric acid, γ-hydroxybutyric acid, α-hydroxyisobutyric acid, glycolic acid, α-hydroxycaproic acid, maleic acid, tartaric acid and propionic acid.SELECTED DRAWING: Figure 15