Abstract: Provided is a pipe connection device. The pipe connection device includes an adapter including a hollow pipe and a ring-shaped protruding end extending in the diameter direction of the hollow pipe from one end of the hollow pipe in the longitudinal direction, a ring flange formed in a ring shape and mounted so as to surround the outer circumferential surface of the protruding end and to be axially rotatable about a central axis of the hollow pipe in the longitudinal direction but not to be movable in the longitudinal direction of the hollow pipe, and a fastening unit configured to join two different ring flanges to each other in a stacked structure so that one end of one of two different hollow pipes in the longitudinal direction and one end of the remaining one of the two different hollow pipes in the longitudinal direction are forcibly secured to each other.