To provide a gas sensor capable of prolonging a useful life.

In a heater 100 used in an oxygen sensor, a brazing material 160 whose main component is silver is used to braze and bond an electrode terminal 130 to an electrode pad 150. When performing brazing, the opposing part 131 of the electrode terminal 130 is sifted to the rear end side and arranged with a center position M in the direction of the axis O of the electrode pad 150 as a reference. In other words, in the direction of the axis O, the opposing part 131 of the electrode terminal 130 is arranged from the center part 152 to the rear end part 153 of the electrode pad 150 and is not arranged at the distal end part 151. Since brazing by the brazing material 160 is performed in the state, the opposing part 131 of the electrode terminal 130 is bonded to the electrode pad 150 at a position near the rear end part 153 of the electrode pad 150. Then, the brazing material 160 is not present at the distal end part 151 of the electrode pad 150.