PURPOSE: To manufacture a can body with an uniform height around the periphery after bulging, by previously providing a side seam margine of a blank can drum and providing cut-off corners on its neighborhood.

CONSTITUTION: The blank can drum 15 is cylindrically rounded and both sides thereof are lap sealed to form a side seam 14 to product a straight can drum 16. Then, a part 13 in a longitudinal part of the straight can drum 16 is bulged by using a split mold project in the radial direction to reduce the height of the can to form the can drum 12. The upper ends (cut-off parts) 21 of the lap seal margines 17, 18 on the both sides of the can drum 12 are removed. In this manufacturing process, elongations of the side seam 14 and its neighborhood are small to cause the reduction of the can height compared with the other parts. Thus the bulged can with the uniform height around the periphery is easily manufactured.