To certainly maintain a gap between the inner peripheral wall face of a cable protective pipe and the outer periphery of an outer cable and surely fill a filler by providing a gap maintaining means maintaining the gap between the cable and the inner peripheral wall face of the protective pipe for filling the filler.

A cable protective pipe 7 slightly longer in length that a through hole 2a at the deflection section of a concrete skeleton 2 is formed. A spiral lug serving as a gap maintaining means for filling a filler is protruded on the inner peripheral wall face of the cable protective pipe 7 over the whole length of the protective pipe 7. The spiral lug surely exists in the range of the cable protective pipe 7 at the deflection section of the concrete skeleton 2. When the filler is filled in the inner spaces of the cable protective pipes 7, 9 after a PC cable is stretched, the filler is surely filled by the spiral lug between the outer periphery of the PC cable and the inner peripheral wall face of the cable protective pipe 7 at the deflection section.