Provided is a technology pertaining to: a metal tube that has a high dimension accuracy without the need of cutting of tube end parts after tube expansion, and that has an outer diameter of 150-3000 mm and a thickness of 2-50 mm; and a manufacturing method for the metal tube. This method includes: a tube end part expansion step for expanding tube end parts 11 at both ends of an element tube 1; and an internal pressure application step for, after the tube end part expansion step until an internal pressure p (MPa) according to a change of an axis pushing amount s (mm) indicating a pushing amount at both ends of the element tube 1 in the tube axial direction with respect to tube endmost sections 12 reaches a preset maximum internal pressure pmax (MPa), expanding the element tube 1 by applying the internal pressure p to the entirety of the inside of the element tube 1, wherein p and s satisfy formula (2): 5×(p/pmax)×(a/200)×L₀≤s≤(p/pmax)×(a/200)×L₀. In formula (2), 'a' represents a preset tube expansion percentage (%) and 'a' satisfies 0.30≤a≤5.0, and L₀ represents an average length (mm) of the element tube.