To provide a method of forming a metal cylindrical body, capable of punching or drawing continuously without applying an excessive load to a blank.

The method of forming the metal cylindrical body 26 for manufacturing a bottomless cylindrical body from a flat thin plate B includes: a punching process for forming a round punched part 21, that is a round hole, by punching a part of the thin plate; a formation process of a flanged cylindrical member for forming the flanged cylindrical member 23 by lowering an upper pressing member 14 set above the thin plate, and pushing an outer peripheral edge 22 of the round punched part upward to expand while constraining by an inner wall of the upper pressing member 14; and a separation process for cutting the flange part 25 connected to a cylindrical base 24 by projecting a top edge 19 of a cylindrical cutter 18 toward the cylindrical base 24 to butt to the cylindrical base 24 of the flanged cylindrical member in which a cylindrical die is intruded.