Useful as a catalyst component for polymerizing olefin is the transition metal compound of the present invention represented by Formula (I): wherein M represents a transition metal compound of the fourth group in the periodic table; X represents a &sgr; bonding ligand; Y represents a Lewis base; T represents a group containing a &sgr; bonding atom; E is a specific group containing an atom which can coordinate with M via a lone pair; q is 1 or 2 and represents [(valency of M)−2]; r represents an integer of 0 to 3; R1 to R4 represent a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing hydrocarbon group, a silicon-containing group or a hetero atom-containing group.