A micro vacuum gauge includes a substrate, a floating structure that is held above the substrate by a supporting structure extending from the substrate in a state where the floating structure is thermally isolated from the substrate, a heat generator that is arranged in the floating structure to generate heat, and a temperature sensor that is arranged in the floating structure to measure a difference in temperature between the substrate and the floating structure. A second member having a lower emissivity than a first member surrounding the heat generator and the temperature sensor is formed at least on a surface of the floating structure by being joined to the first member.