Abstract: In a gas sensor, a powder compact seals a void space between an inner peripheral surface of metal-made main hardware and a sensor element, and the inner peripheral surface has arithmetic average roughness of 0.5 to 5 ?m. The gas sensor includes supporters, which are arranged in a penetration hole of the main hardware, which allow the sensor element to penetrate therethrough, and which press the powder compact in sandwiching relation from both sides in an axial direction. A surface of at least one of the supporters has the arithmetic average roughness of not more than 0.5 ?m.

Abstract: In a main metal piece 60 and an inner cylinder 70 serving as cylindrical bodies before welding, a second end surface 75 is an inclined surface that inclines toward an end portion opposite from the second end surface 75 as the second end surface 75 extends toward the center axis, and an angle ?2a is 5° to 15°. Thus, the distance between a first end surface 65 and the second end surface 75 positioned in resistance welding increases toward the center axis, and an angle ?c (=angle ?2a) between the first end surface 65 and the second end surface 75 is 5° to 15°.

Abstract: In a gas sensor 10, a powder compact 45a seals a void space between an inner peripheral surface 42c of metal-made main hardware 42 and a sensor element 20, and the inner peripheral surface 42c has arithmetic average roughness Ra of 0.5 to 5 ?m. The gas sensor 10 includes supporters 44a and 44b, which are arranged in a penetration hole of the main hardware 42, which allow the sensor element 20 to penetrate therethrough, and which press the powder compact 45a in sandwiching relation from both sides in an axial direction. A surface of at least one of the supporters 44a and 44b has the arithmetic average roughness Ra of not more than 0.5 ?m.

Abstract: In a gas sensor, a powder compact seals a void space between an inner peripheral surface of metal-made main hardware and a sensor element, and the inner peripheral surface has arithmetic average roughness of 0.5 to 5 ?m. The gas sensor includes supporters, which are arranged in a penetration hole of the main hardware, which allow the sensor element to penetrate therethrough, and which press the powder compact in sandwiching relation from both sides in an axial direction. A surface of at least one of the supporters has the arithmetic average roughness of not more than 0.5 ?m.

Abstract: Among first and second swaged sections, the second swaged section begins to be swaged prior to the first swaged section. Hence, a strong force can be prevented from acting on a rubber plug in a free state at a time and the first swaged section can begin to be swaged in such a state that a portion of the rubber plug that corresponds to the second swaged section is aligned as compared to the case where the first and second swaged sections begin to be simultaneously swaged. This prevents the position of the rubber plug from being significantly varied during swaging and also prevents the rubber plug from protruding from an outer tube.

Abstract: In a main metal piece 60 and an inner cylinder 70 serving as cylindrical bodies before welding, a second end surface 75 is an inclined surface that inclines toward an end portion opposite from the second end surface 75 as the second end surface 75 extends toward the center axis, and an angle ?2a is 5° to 15°. Thus, the distance between a first end surface 65 and the second end surface 75 positioned in resistance welding increases toward the center axis, and an angle ?c (=angle ?2a) between the first end surface 65 and the second end surface 75 is 5° to 15°.

Abstract: In a gas sensor 10, a powder compact 45a seals a void space between an inner peripheral surface 42c of metal-made main hardware 42 and a sensor element 20, and the inner peripheral surface 42c has arithmetic average roughness Ra of 0.5 to 5 ?m. The gas sensor 10 includes supporters 44a and 44b, which are arranged in a penetration hole of the main hardware 42, which allow the sensor element 20 to penetrate therethrough, and which press the powder compact 45a in sandwiching relation from both sides in an axial direction. A surface of at least one of the supporters 44a and 44b has the arithmetic average roughness Ra of not more than 0.5 ?m.

Abstract: Among first and second swaged sections, the second swaged section begins to be swaged prior to the first swaged section. Hence, a strong force can be prevented from acting on a rubber plug in a free state at a time and the first swaged section can begin to be swaged in such a state that a portion of the rubber plug that corresponds to the second swaged section is aligned as compared to the case where the first and second swaged sections begin to be simultaneously swaged. This prevents the position of the rubber plug from being significantly varied during swaging and also prevents the rubber plug from protruding from an outer tube.