An infrared detector capable of detecting an infrared spectrum having a wide bandwidth using a broadband light absorber. The infrared detector including a substrate, a light absorber disposed apart from the substrate at a distance, and a pair of thermal legs configured to support the light absorber such that the light absorber is spaced apart from the substrate by the distance. The light absorber includes at least one thermistor layer having a resistance value that varies according to temperature and at least two resonator layers disposed on at least one of upper and lower surfaces of the at least one thermistor layer.