Abstract: The invention proposes a method for manufacturing a seamless steel pipe having high strength, high toughness, and high formability for an airbag. A method for manufacturing a seamless steel pipe comprising a process for manufacturing a raw material for steel pipe having a composition containing 0.01 to 0.10% of C, 0.5% or less of Si, 0.10 to 2.00% of Mn, more than 1.0% and 2.0% or less of Cr, and 0.5% or less of Mo to form the seamless steel pipe, a process for drawing the seamless steel pipe in cold working, and a quenching and tempering process for heating the seamless steel pipe to Ac3 transformation point or more and 1050° C. or less and then quenching, then tempering at 450° C. or more and Ac1 transformation point or less is proposed. A method for manufacturing a seamless steel pipe where the cold drawing process is replaced after the quenching and tempering process is proposed. The composition may further contain, in addition to the composition, one or two or more selected from 1.0% or less of Cu, 1.