PROBLEM TO BE SOLVED: To provide a method for connecting piping which can surely prevent the leakage from the connected portion when the end portion of the piping has been connected by an electric fusion method while preventing water from reaching the end portion (the end portion on the downstream side) of the piping in a water supply state. SOLUTION: In the method for connecting piping, the end portion 5 is connected by the electric fusion method by cutting off water of the inside 2 of the piping 1 made of polyethylene. A snap tap 9 with a saddle is attached to the piping 1. Then, an expandable blocking bag 6 and a water absorbing member 7 are inserted into the inside 2 of the piping 1 via the snap tap 9 with the saddle such that the water absorbing member 7 is located on the downstream side of the blocking bag 6. The inside 2 of the piping 1 is sealed by expanding the blocking bag 6 by supplying gas into the blocking bag 6. The water leaked to the downstream side from the clearance between the inside surface 4 of the piping 1 and the blocking bag 6 is absorbed by the water absorbing member 7. Then, the end portion 5 of the piping 1 is connected by the electric fusion method. After the electric fusion work has been completed, the blocking bag 6 and the water absorbing member 7 are taken out from the inside 2 of the piping 1 via the snap tap 9 with the saddle. COPYRIGHT: (C)2009,JPO&INPIT