To provide an inexpensive infrared detector of which output characteristics can be evaluated even in the stage of a wafer halfway in manufacture.

The infrared detector 10 is provided with both a membrane Ma formed as a thin-walled part of a substrate 1 and a thermocouple T to be used as an infrared detection element. A hot junction Th of the thermocouple T is formed on the membrane Ma, and a cold junction Tc of the thermocouple T is formed on the substrate 1 outside the membrane Ma. The infrared detector detects infrared rays on the basis of an electromotive force associated with a temperature difference which occurs between the hot junction Th and the cold junction Tc of the thermocouple T due to the reception of infrared rays. A heater H is provided for the vicinity of the thermocouple T, and a hot-junction temperature-sensitive resistance element Sh and a cold-junction temperature-sensitive resistance element Sc are each provided on the membrane Ma in the vicinity of the thermocouple T and on the substrate 1 outside the membrane Ma.