Disclosed is a steel sheet having a tensile strength of 1180 MPa or more and excels in workability and cold brittleness resistance. The high-strength steel sheet contains 0.10% to 0.30% of C, 1.40% to 3.0% of Si, 0.5% to 3.0% of Mn, 0.1% or less of P, 0.05% or less of S, 0.005% to 0.20% of Al, 0.01% or less of N, and 0.01% or less of O, with the remainder including Fe and inevitable impurities. The steel sheet has a ferrite volume fraction of 5% to 35% and a bainitic ferrite and/or tempered marten site fraction of 60% more based on the total volume of structures determined by observation of the structures at a position of a depth one-quarter the thickness of the sted sheet under a scanning electron microscope, has a MA constituent volume fraction of 6% or less (e»duding0%) based on the total volume of structures determined by observation of the structures under an optical microscope, and has retained austenite volume fraction C£5%OT mere based on the total volume of structures determined by X-ray diffracttometry of the retained austenite.
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