PROBLEM TO BE SOLVED: To provide a pipe capable of achieving an efficient flow within a pipe.SOLUTION: In a pipe, at least two branch pipes are joined to one main pipe, and joined to each other at a predetermined branching angle. Both of joint surfaces of the branch pipes joined to a joint, which is a joined part of the pipe, are orthogonal to the central axis of the pipe. When a part, to which pipe walls of the opposed branch pipes are joined, is set as a first crotch part, the pipe comprises a second crotch part that is configured by extending the first crotch part by a predetermined distance into the joint.
