PURPOSE: To produce economically a metallic vessel having a seam which is highly strong and is uniformly constructed by forming an adequate arc part to the top end of the flange of a body plate, setting the adequate tentative fitting condition for the flanges of top and bottom plates and rolling and seaming the flanges.

CONSTITUTION: An arc part which has a central angle of 0°W180° and of which the radius of curvature is equal to the min. radius of curvature of a flange 2 of a body plate in a desired seam part is formed in the top end of the flange 2 next to the body part 2' of the body plate and more preferably an arc part having an adequate central angle of 0°W180° at which said part does not abut on the outside of said arc part during the process of rolling and seaming is preliminarily formed in the top end of a flange 1 next to the body part 1' of top and bottom plates. The end parts of the flanges are then rolled and seamed by using a rolling and seaming roll 14 having a forming groove R continued with the concentrical circles of the radii of curvature centering respectively at the points 3, 4 of the distance equal to 1/2 of the sum of the thicknesses of the top and bottom plates 1' and the body plate 2' and a chuck ring having the forming groove 16 corresponding thereto. The seam part is thus formed.