GAS SENSOR

A gas sensor (200) including a sensor element (10) having electrode pads (11a-12b); a separator (166); and a plurality of metal terminals (21a, 21b, 22a, 22b) each having a body portion (21a1) and a front end portion (21a2), and being insulated from each other by the separator. The separator has an element storage portion (168) penetrating in the axial-line direction or recessed toward a rear side from a front facing surface of the separator, the element storage portion has a first storage space (168a) at a front side thereof and a second storage space (168b) at a rear side thereof, the second storage space has a rotation restriction wall (168w) configured such that a relative rotation allowable angle 2θ between the sensor element and the separator is smaller than in the first storage space, and the rear end side of the sensor element is stored in the second storage space.