It is an object of the present invention to provide an excellent enhancer for an osteogenesis accelerator that can enhance the activity of BMP as an osteogenesis accelerator. Another object of the present invention is to provide a method of screening for a novel enhancer for an osteogenesis accelerator.The present invention relates to an enhancer for an osteogenesis accelerator, which comprises a compound having a TGF-.beta. selective inhibitory activity as an active ingredient, the enhancer being administered with an osteogenesis accelerator containing BMP as an active ingredient either simultaneously or sequentially, and to a method of screening for an enhancer for an osteogenesis accelerator, comprising using a TGF-.beta. inhibition as a measure for discovering the enhancer.