A structure of steel cable fastener is provided for eliminating a returning force caused by twisting stress induced in a steel cable when the steel cable is stretched and fixed by the fastener, which induces a stress due to fixing of a fixing end of the steel cable. Such a returning force makes the operation and adjustment of mounting a locking cap to the steel cable difficult and also induces damage and wear of a fixing end of the steel cable due to twisting stress induced in the steel cable. The structure of the steel cable fastener includes a bearing retainer that carries a bearing device and arranged inside the locking cap to secure an end of the steel cable and a resilient element arranged between the bearing retainer and the locking cap for relief of twisting stress induced in the steel cable through the rotation of the bearing device.