Manufacturing Method of Welded Pipe and Manufacturing Device of Welded Pipe

A manufacturing device of a welded pipe, comprising:

• means for bending a stainless steel strip having a thickness of 0.15 mm or more and 0.45 mm or less while conveying the stainless steel strip to thereby form a pipe;
• and means for welding a butting part of the formed pipe by irradiating the butting part with a laser beam while applying compressive stress to the butting part by using a set of squeeze rolls,
• wherein an irradiation position of the laser beam is located on an upstream side in a pipe conveyance direction with respect to a position of a rotation axis of the squeeze roll,
• a size of a spot diameter of the laser beam at the irradiation position of the laser beam is 0.60 mm or more and 1.2 mm or less, and
• the manufacturing device further includes a gas nozzle for blowing inert gas at the butting part irradiated with the laser beam, and
• a position at which the inert gas is blown on the butting part from the gas nozzle is located within an area from the irradiation position of the laser beam to the position of the rotation axis of the squeeze roll.