Abstract: An unbonded PC steel strand used for posttensioning concrete comprising a PC steel strand composed of a plurality of stranded wires, a thin transparent lacquer coating on the outer surface of the PC steel strand, the lacquer coating being able to be broken when the PC steel strand is subjected to tension or posttensioning concrete, a filler applied around the lacquer coating, and a synthetic resin sheath covering the lacquer and filler coated PC steel strand. A method of manufacturing the unbond PC steel strand comprising steps of annealing the PC steel strand at a low temperature to remove strain, coating the outer surface of the PC steel strand with lacquer, applying a greaselike corrosion inhibitor to the surface of this lacquer coating, and sheating the coated PC steel strand with an outer synthetic resin sheath.