An infrared detector 1 having a bolometer element 11 and a reference element 21 is provided with a bolometer thin film 22 supported on a surface of a substrate 10while spaced apart from the surface of the substrate 10, a metal film 23 for heat dissipation formed on a surface of the bolometer thin film 22 via an insulating film 31, wherein the surface of the bolometer thin film 22 faces the substrate 10, and a plurality of metal columns 25 connected thermally with the metal film 23 for heat dissipation and the substrate 10. Since heat generated from a photodetecting portion 22aby infrared rays is efficiently dissipated to the substrate 10 via the insulating film 31, the metal film 23 for heat dissipation, the metal columns 25, and a metal film 24 for heat dissipation on the side of the substrate, only temperature variation caused by variation in use environment can be measured accurately, and downsizing can be achieved while reducing the influence of temperature variation in use environment.