Abstract: The invention relates to a device for the radial holding or supporting of the envelope of a bundle of tubes and spacer plates of a steam generator or boiler, constituted by stops or abutments traversing the wall of the bundle envelope and fixed to the wall level with the spacer plates. The abutments are distributed over the periphery of each spacer plate in order to radially separate the bundle envelope from the pressure envelope of the steam generator and to exert rigid supporting stresses between the spacer plates and the bundle envelope. The abutments are adapted for sliding on the inner face of the pressure envelope. Each abutment is constituted by a first part which comes into contact with the inner face of the pressure envelope, a second part and a third part coming into contact with the spacer plate. The second part serving as the intermediary between the first and third parts. The first part has a first thread permitting its fixing by screwing to the bundle envelope and a second thread.