Abstract: A pipe coupling apparatus includes a coupling case for surrounding an outer periphery of an existing pipe in a sealed state. The coupling case defines a pipe coupling opening for coupling a new pipe to the coupling case, and an executing opening for use in cutting a branching opening in the existing pipe. A lid is mounted on the coupling case for sealing the executing opening. The branching opening is formed in a way to prevent a fluid from flowing out of the executing opening. The coupling case houses a first valve operable from outside the coupling case to open and close the coupling opening, and a second valve also operable from outside the coupling case to move into the existing pipe through the branching opening for closing one of passages defined by the existing pipe and communicating with the branching opening.