A device for producing an essentially T-shaped hollow profile or a hollow profile provided with at least one branch. The device may have a multipart mold which is intended for internal high pressure forming, in which a hollow profile having at least one initially dome-like branch can be produced. The device may also have a tool at the branch, this tool being designed for opening the branch at the end face after the forming operation. The tool is designed as a cutting device having a parting slide displaceable essentially transversely to the axis of the branch.