To provide a device and a method for manufacturing an electric resistance welded pipe which has high welding strength and has no depression at welded spots.

A concave curve 28 which has a longitudinal section of an arc with R in radius is formed all round the side surface of a squeeze roll 8. A lower flange 29 is made beneath the concave curve and an upper flange 30 is made above the concave curve. Facing the concave curve 28, a virtual line L including the center O1 of the radius R is set on a parallel with a rotating shaft 22 of the squeeze roll 8. When the distance between the virtual line L and the lower flange 29 is a, and the distance between the virtual line L and the upper flange 30 is b, a is shorter than b. At the time of welding the electric resistance welded pipe p, a gap between the upper flanges 30, 30 of a pair of the squeeze rolls is formed and a steel plate is passed between the concave curves 28, 28. Thereby the plate is uprolled and welding parts M of both ends protrude in the gap. The both ends are gradually welded from the lower end to the upper end.