Provided is a method for producing an optically active compound, in more detail, for producing an optically active compound by asymmetric hydrogenation in a high yield and asymmetric yield. The present invention also provides a catalyst for asymmetric synthesis for the above production method, especially a catalyst for asymmetric hydrogenation, containing a transition metal complex. Further, the present invention provides a new diphosphine compound useful as a ligand of the above transition metal complex and a new transition metal complex containing the above diphosphine compound. The present invention relates to a diphosphine compound represented by the following formula (1): a transition metal complex using the compound, a catalyst for asymmetric synthesis comprising the above transition metal complex and a method for producing an optically active compound using the above catalyst for asymmetric synthesis.