A method of producing a metallic shell for a spark plug from a cylindrical metal blank cut to a predetermined length, the metallic shell including a screw shaft portion to be screwed into a spark plug mounting tap hole of an engine, a stop portion that is disposed on one axial end side of the screw shaft portion and larger in diameter than the spark plug mounting tap hole, and a through hole extending through the metallic shell in an axial direction of the metallic shell, the method comprising the step of: preparing a first intermediate article including a large diameter portion (Ma) and a tapered portion (Mc) which are to be later formed into the stop portion of the metallic shell and a small diameter portion (Mb) which is to be later formed into the screw shaft portion of the metallic shell, characterized in that the first intermediate article is prepared by using a first die including a first large diameter cavity which is larger in diameter than the metal blank and configured to form a portion of the metal blank which is to be later formed into the stop portion of the metallic shell, a first small diameter cavity which is smaller in diameter than the metal blank and configured to form a portion of the metal blank which is to be later formed into the screw shaft portion of the metallic shell, a curved tapered cavity between the first large diameter cavity and the first small diameter cavity, wherein the curved tapered cavity has one axial end connected with an axial end of the first small diameter cavity in an axially opposed relation thereto, and an oil drain cavity between the first large diameter cavity and the curved tapered cavity, wherein the oil drain cavity is substantially same in diameter as the metal blank, wherein the metal blank is inserted in the first large diameter cavity and extruded to allow a configuration of the metal blank to conform to the first large diameter cavity, the oil drain cavity, the curved tapered cavity and the first small diameter cavity while being pressed by a punch. preparing a first intermediate article including a large diameter portion (Ma) and a tapered portion (Mc) which are to be later formed into the stop portion of the metallic shell and a small diameter portion (Mb) which is to be later formed into the screw shaft portion of the metallic shell, characterized in that the first intermediate article is prepared by using a first die including a first large diameter cavity which is larger in diameter than the metal blank and configured to form a portion of the metal blank which is to be later formed into the stop portion of the metallic shell, a first small diameter cavity which is smaller in diameter than the metal blank and configured to form a portion of the metal blank which is to be later formed into the screw shaft portion of the metallic shell, a curved tapered cavity between the first large diameter cavity and the first small diameter cavity, wherein the curved tapered cavity has one axial end connected with an axial end of the first small diameter cavity in an axially opposed relation thereto, and an oil drain cavity between the first large diameter cavity and the curved tapered cavity, wherein the oil drain cavity is substantially same in diameter as the metal blank, wherein the metal blank is inserted in the first large diameter cavity and extruded to allow a configuration of the metal blank to conform to the first large diameter cavity, the oil drain cavity, the curved tapered cavity and the first small diameter cavity while being pressed by a punch.