The present invention provides an osteogenesis enhancer comprising a molecule capable of acting on RANKL that enhances differentiation, proliferation, maturation, or calcification of osteoblasts or cells capable of differentiating into osteoblasts. A pharmaceutical composition for treatment or prevention of bone metabolism diseases associated with osteopenia, which comprising, as an active ingredient, a compound that acts on RANKL located on osteoblasts or cells capable of differentiating into osteoblasts and promotes differentiation, proliferation, maturation, or calcification of osteoblasts or cells capable of differentiating into osteoblasts is provided.
