An underground power cable having an optical fiber sensor for measuring temperature distribution is disclosed. In the power cable, an optical fiber for measuring temperature distribution is received in a stainless steel tube having excellent strength, and this optical tube is interposed between a core and a sheath of the power cable. When arranging the optical tube in the power cable, a supporting material having a relatively low strength than the optical tube is arranged in the cable together in order to prevent the optical fiber from being damaged by external force and prevent the inner insulation layer from being broken down by the optical tube. In addition, a fixing tape for fixing the optical tube in contact with the core may be added to prevent the optical tube from being bent seriously or inclined to one side when the cable is bent.