There are provided Idbf (inhibitor of Dvl and bone formation) which is a novel Dvl-binding protein that binds to Dvl to inhibit signal transduction carried out through the Wnt/β-catenin signaling pathway, a gene for coding for the same, the use thereof, and the use of an inhibitor of the Idbf. The Idbf was known to be expressed by activation of the Wnt/β-catenin signaling pathway and bind to Dvl to block signal transduction carried out through the Wnt/β-catenin signaling pathway. Therefore, the Idbf can be used in development of medicines for inhibiting the signal transduction carried out through the Wnt/β-catenin signaling pathway, and an Idbf inhibitor can be used in preparation of medicines for activating the signal transduction carried out through the Wnt/β-catenin signaling pathway.