An infrared detector comprising: a substrate; a resonant unit spaced apart from the substrate, the resonant unit configured to generate heat by inducing resonance at a plurality of wavelengths of incident infrared light; a thermistor layer having a plate structure and configured to support the resonant unit and be spaced apart from the resonant unit; and a connection unit configured to: support the thermistor layer such that the thermistor layer is spaced apart from the substrate, and electrically connect the thermistor layer to the substrate; and characterized in that: the resonant unit comprises a first sub-resonator configured to absorb first polarized light of a first wavelength band, a second sub-resonator configured to absorb second polarized light of the first wavelength band, a third sub-resonator configured to absorb first polarized light of a second wavelength band and a fourth sub-resonator configured to absorb second polarized light of the second wavelength band, the second polarized light being perpendicular to the first polarized light, and the first wavelength band and the second wavelength band partially overlapping each other or completely different from each other; the first and second sub-resonators are spaced apart from one another; the third and fourth sub-resonators are spaced apart from one another; and the thermistor layer has an area the same as or slightly greater than that of the resonant unit, and is adapted to support the first to the fourth sub-resonators such that the heat generated from the sub-resonators varies a resistance value of the thermistor layer. a substrate; a resonant unit spaced apart from the substrate, the resonant unit configured to generate heat by inducing resonance at a plurality of wavelengths of incident infrared light; a thermistor layer having a plate structure and configured to support the resonant unit and be spaced apart from the resonant unit; and a connection unit configured to: support the thermistor layer such that the thermistor layer is spaced apart from the substrate, and electrically connect the thermistor layer to the substrate; support the thermistor layer such that the thermistor layer is spaced apart from the substrate, and electrically connect the thermistor layer to the substrate; and characterized in that: the resonant unit comprises a first sub-resonator configured to absorb first polarized light of a first wavelength band, a second sub-resonator configured to absorb second polarized light of the first wavelength band, a third sub-resonator configured to absorb first polarized light of a second wavelength band and a fourth sub-resonator configured to absorb second polarized light of the second wavelength band, the second polarized light being perpendicular to the first polarized light, and the first wavelength band and the second wavelength band partially overlapping each other or completely different from each other; the first and second sub-resonators are spaced apart from one another; the third and fourth sub-resonators are spaced apart from one another; and the thermistor layer has an area the same as or slightly greater than that of the resonant unit, and is adapted to support the first to the fourth sub-resonators such that the heat generated from the sub-resonators varies a resistance value of the thermistor layer. the resonant unit comprises a first sub-resonator configured to absorb first polarized light of a first wavelength band, a second sub-resonator configured to absorb second polarized light of the first wavelength band, a third sub-resonator configured to absorb first polarized light of a second wavelength band and a fourth sub-resonator configured to absorb second polarized light of the second wavelength band, the second polarized light being perpendicular to the first polarized light, and the first wavelength band and the second wavelength band partially overlapping each other or completely different from each other; the first and second sub-resonators are spaced apart from one another; the third and fourth sub-resonators are spaced apart from one another; and the thermistor layer has an area the same as or slightly greater than that of the resonant unit, and is adapted to support the first to the fourth sub-resonators such that the heat generated from the sub-resonators varies a resistance value of the thermistor layer.