To make freely executable a construction work without any restraint of the place of construction by providing a cable type sensor for transmitting the tension of a fixed point moving according to a breakdown through each conductor in the cable, and transmitting the tension to the fixed point, which does not move, by 100% when the cable type sensor is extended according to the generation of a crack of the ground.

The conductor of a twisting line whose extensibility is known is inserted into a semi-circular groove. The diameter of the semi-circle is made larger than the diameter of the conductor. A lubricating oil is injected into the groove so that abrasion resistance with a rod when the twisting line is extended can be decreased. A paper tape is wound around the expandable rod so that the conductor can be prevented from dropping from the groove. The rod is made of vinyl chloride, NBR, rubber, and spandex or the like. The position of the cut part can be estimated by transmitting a pulse by a pulse reflection method, and measuring a time until the pulse is reflected from the cut part.