Abstract: A pipe coupler is capable of preventing a fluid flowing along pipes from coming into direct contact with the pipes made of metal materials, a body, and tie rings, thereby preventing corrosion of the pipes. The pipe coupler is also capable of preventing pipes, even if the pipes made of different kinds of materials are connected, from being indirectly connected to each other by way of a fluid flowing along the inside of the pipes, thereby preventing electric corrosion of the pipes caused by the micro current contained in the fluid. The pipe coupler is also capable of absorbing dimensional differences between the pipes having different sizes.