<p>The present invention provides a high-responsiveness and high-accuracy thermal gas sensor configured to enable gas to be analyzed based on a variation in heat conductivity. The thermal gas sensor includes a substrate 2 with a cavity portion 5, a thin-film support 6 stacked in the cavity portion and comprising a plurality of insulating layers 8a and 8b, and a first heating member 3 and a second heating member 4 both sandwiched between the insulating layers in the thin-film support. The second heating member 4 is located around a periphery of the first heating member 3. The first heating member 3 is controlled to a temperature higher than a temperature to which the second heating member 4 is controlled. The concentration of ambient gas is measured based on power applied to the first heating member 3.</p>
