A ruthenium-phosphine complex is disclosed, which is represented by formula (I):[Ru(R-BINAP)MCl.sub.k ].sub.l X.sub.m (I)wherein R-BINAP represents a tertiary phosphine represented by formula (II): ##STR1## wherein R represents hydrogen atom or methyl group; M represents Zn, Al, Ti, or Sn; X represents N(C.sub.2 H.sub.5).sub.3 or CH.sub.3 CO.sub.2 ; in the case that X represents N(C.sub.2 H.sub.5).sub.3, l is 2 and m is 1, and when M represents Zn, then k is 4, when M represents Al, then k is 5, and when M represents Ti or Sn, then k is 6; and in the case that X represents CH.sub.3 CO.sub.2, l is 1 and m is 2, and when M represents Zn, then k is 2, when M represents Al, then k is 3, and when M represents Ti or Sn, then k is 4.