A catalyst contains a metal complex compound represented by the following general formula (I). In the formula (I), M is a metal ion such as ruthenium, L1 is a cyclic or acyclic, neutral or minus 1-valent unsaturated hydrocarbon group of 1 to 30 carbon atoms which may have a substituent, L2 and L3 are each independently chlorine or the like, and L4 is a compound bonded to M through phosphorus or arsenic and represented by the following general formula (IIa) or (IIb). In the formulas (IIa) and (IIb), E is phosphorus or arsenic, Y1 is oxygen or sulfur, Y2, Y3 and Y4 are each independently a hydrogen atom, an aryl group or the like, and H is a hydrogen atom.