To provide a catalyst for polymerizing an olefin for efficiently introducing a terminal vinyl structure into an olefin polymer of any structure, a transition metal compound for use in synthesizing the catalyst, and a method of producing an olefin (co)polymer having a terminal vinyl structure using the above catalyst for polymerizing an olefin.

The new transition metal compound is represented by formula: M1L1mL2x-m-1H. In the formula, M1 represents a group 4 transition metal in the periodic table, L1 represents an indenyl group comprising an electron withdrawing group, L2 represents an unsubstituted indenyl group, x represents the valence of the transition metal M1, and m is not smaller than 1 and not greater than 3, provided that L1 may be the same or different if there are multiple L1 groups. The catalyst for polymerizing an olefin is comprised of the transition metal compound, an organic aluminumoxy compound, and/or a compound that forms an ion-pair by reacting with the transition metal compound.