To expand the versatility and facilitate conduction of a cable, in an underground buried protecting pipe for protecting, from earth load or impacts, various kind of cables such as electric power lines, phone lines, and optical fiber constructed in the ground.

A underground buried protecting pipe is constituted by forming a lot of hemispherical projections 32 on an inner side of a cylindrical pipe element 3 and connecting a plurality of pipe elements 3 is bendably connected with each other. Bending of each pipe elements 3 makes the whole underground buried protecting pipe bendable in an arbitral direction. When a cable in the underground buried protecting pipe is conducted, the cable is brought into point- contact with the hemispherical projections 32 at low-friction in each pipe element 3.