To provide a renewing apparatus for a junction pipe or a branch pipe whose tempo ral installation is simple and easy to be handled and which does not cause stagnation of pig and provide a renewing method for a junction pipe or a branch pipe by which operation and adjustment at the time of polishing and coating process are made easy to carry out even by an unskilled worker and a work can be carried out on the junction pipe or the branch pipe without requiring dividing the pipes by the diameter and without requiring shift of the temporal installation in the midst of the work.

An opened end of a main pipe 11 of a junction or branch pipe 1, which is an object to be renewed, to a suction apparatus 4 through a pig/coating material receiving apparatus 2 and meanwhile, open ends of respective branch pipes 12, 13, 14 are connected to a suction pipe 6 having an opening and closing valve 7 through a pig/coating material insertion part 5. Using a pipe renewing apparatus connected with such pipes, pig or pig together with a coating material is inserted into the pig/coating material insertion part 5 of an optional branch pipe: the suction apparatus 4 is started to keep the inside of the pipeline 1 at negative pressure: the opening/closing valve 7 of the suction pipe 6 formed in the pig/ coating material insertion part 5 is operated to introduce outer air while controlling the intake amount: the pig is moved by the pressure difference generated in front and in rear sides of the pig to polish or coat the inner surface of pipes.