A piping structure and a process, with which it is possible to form an opening in a pipe while preventing shavings produced from cutting from entering the pipe. A process for forming an opening in a pipe, including: a step of enclosing the pipe with a case divided in a circumferential direction R of the pipe; a skin formation step of cutting an outer surface of the pipe with a cutting tool arranged in the case, thereby forming a bottomed groove, which is formed as a skin, on the pipe; a suction step of sucking shavings produced from cutting, together with a gas in the case in order to remove the shavings; and breaking the skin to form the opening after performing the skin formation step and the suction step.