PURPOSE: To attain to re-utilize a catalyst, by distilling a solution from which a supported transition metal catalyst was removed as an insoluble part after contact treatment to remove at least a high b.p. substance having a b.p. higher than that of a volatile transition metal compound and using the transition metal dissolved in the obtained solvent.

CONSTITUTION: In a method for preparing a supported transition metal catalyst by the contact treatment of a volatile transition metal compound (e.g., titanium tetrachloride) dissolved in a solvent (e.g., hexane) and a carrier (e.g., silica), the transition metal compound dissolved in the solvent, which is obtained by distilling a solution from which the supported transition metal catalyst was removed as an insoluble part after contact treatment to remove at least a high b.p. substance having a b.p. equal to or more than that of the volatile transition metal compound, is used. By this simple method, the recovery and re-utilization of the volatile transition metal compound can be achieved without lowering the capacity of the obtained catalyst.