Gas sensor and method for producing gas sensor

Provided is a gas sensor that can improve responsiveness. A gas sensor (10) comprises: an electrode part (50) that is provided with at least one electrode pair (70) and that is formed by disposing a first electrode (71) and a second electrode (72) so as to face each other in a first direction with a gap therebetween; and a sensitive membrane (60). When the product of the inter-electrode distance between the first electrode (71) and the second electrode (72) in the first direction and an electrode area at a cut section, of the first electrode (71), orthogonal to the first direction is defined as an inter-electrode volume, the quotient obtained by dividing, by the inter-electrode volume, a voltage applied, by means of a voltage application part (80), to the electrode part (50) is greater than 4.2*1016V/m3 but not greater than 2.0*1025V/m3. The electrode area is not less than 2.5*10-15m2.