A method of producing a spark plug comprising: (a) a step (S110) of combining a tubular metallic shell and an insulator such that the metallic shell covers an outer circumferential surface of a forward end side of the insulator so as to obtain an assembly , the metallic shell having a ground electrode at its forward end portion, the insulator having an axial hole and holding a terminal electrode in the axial hole such that a portion of the terminal electrode on its base end side is exposed from the axial hole; (b) a step (S125) of inserting a portion of the assembly on its forward end side into a pressure container through an opening of the pressure container ; (c) a step (S130) of bringing an insulating member into contact with an outer circumferential surface of a base end side of the insulator over the entire circumference of the base end side in a state in which an axial line (AX) of the assembly and an axial line of the opening coincide with each other, wherein a pressing and energizing section 200 is moved in the insertion direction (ID) of the assembly , wherein an electrode member 270, which is formed of an electrically conductive material and is disposed at the forward end portion of the pressing and energizing section , comes into contact with the metallic shell of the assembly to thereby ground the metallic shell during the producing of the spark plug, wherein via the electrode member , the assembly is further pressed in the insertion direction (ID), and pressing the assembly so as to close the opening by the assembly ; and (d) a step (S135) of pressurizing an interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell , wherein the step (b) includes a step of inserting the portion of the assembly on the forward end side into the pressure container such that a gap formed between an outer circumferential surface of the insulator and an inner circumferential surface of the metallic shell on the forward end side of the assembly is disposed in the pressure container . (a) a step (S110) of combining a tubular metallic shell and an insulator such that the metallic shell covers an outer circumferential surface of a forward end side of the insulator so as to obtain an assembly , the metallic shell having a ground electrode at its forward end portion, the insulator having an axial hole and holding a terminal electrode in the axial hole such that a portion of the terminal electrode on its base end side is exposed from the axial hole; (b) a step (S125) of inserting a portion of the assembly on its forward end side into a pressure container through an opening of the pressure container ; (c) a step (S130) of bringing an insulating member into contact with an outer circumferential surface of a base end side of the insulator over the entire circumference of the base end side in a state in which an axial line (AX) of the assembly and an axial line of the opening coincide with each other, wherein a pressing and energizing section 200 is moved in the insertion direction (ID) of the assembly , wherein an electrode member 270, which is formed of an electrically conductive material and is disposed at the forward end portion of the pressing and energizing section , comes into contact with the metallic shell of the assembly to thereby ground the metallic shell during the producing of the spark plug, wherein via the electrode member , the assembly is further pressed in the insertion direction (ID), and pressing the assembly so as to close the opening by the assembly ; and (d) a step (S135) of pressurizing an interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell , <EOS>