PURPOSE: To finish the pipe having an optional dimension in optional dimension with high accuracy by putting into a pressure container after tightly closing both ends of the metal tube having a corrugation, increasing or decreasing the pressure inside the pressure container and holding for a fixe time by decreasing or increasing the pressure inside the tube.

CONSTITUTION: One part or both parts of a pressure generation devices 6, 7 is actuated to provide a pressure difference P1-P0 on the pressure P1 inside a corrugated metal tube 1 and the pressure P0 of a pressure container 3. At this time in the case of the pressure difference P1-P0 being of minus value, the waveform pitch of the corrugated metal tube 1 is elongated, the outer diameter is reduced and inner diameter is made larger. In the case of being at minus value, the waveform pitch is reversely contracted, the outer diameter is made larger and the inner diameter is reduced. The waveform shape can thus be varied by setting the inner and outer face pressures P1 and P0 of the metal tube having a waveform shape and even the metal tube impossible to form by a primary working can be subjected to a secondary working uniformly in the specified dimension.