A contact fitting has a supporting portion capable of contacting a surface of a sensor element, and a conducting portion protruding in the same direction as the supporting portion and capable of contacting an electrode on the sensor element. Before the contact fitting is attached to the sensor element, a protrusion height of the conducting portion is 90% to 110% of a protrusion height of the supporting portion, and the protrusion heights and are relatively close to each other. The supporting portion and the conducting portion are elastically deformable and are curved in shape. The supporting portion and the conducting portion are arranged along a longitudinal direction of the contact fitting.