An infrared detection device comprising; an infrared detection element , which comprises: a pyroelectric body ; a first light receiving electrode formed on a surface of the pyroelectric body ; a second light receiving electrode formed on a surface of the pyroelectric body ; and a light-sensitivity adjustment member comprising an infrared absorption film arranged on a surface of at least the first light receiving electrode , and configured to make infrared reception sensitivity of the first light receiving electrode higher than that of the second light receiving electrode ; wherein the infrared detection device further comprises an optical element (OE); characterised in that the optical element is configured to direct light from a first infrared- detection target region (TGR1), set as a region targeting a first detection target, to the first light receiving electrode , wherein the first electrode is configured to receive light from the first infrared-detection target region (TGR1), and to direct light from a second infrared-detection target region (TGR2), set as a region targeting mainly a second detection target and part of the first detection target, to the second light receiving electrode wherein the second light receiving electrode is configured to receive light from the second infrared-detection target region (TGR2); and wherein the detection sensitivity is increased for the first infrared-detection target region (TGR1) and is reduced for the second infrared-detection target region (TGR2), such that the first detection target in the first infrared-detection target region is distinguished from the second detection target in the second infrared-detection target region. a pyroelectric body ; a first light receiving electrode formed on a surface of the pyroelectric body ; a second light receiving electrode formed on a surface of the pyroelectric body ; and a light-sensitivity adjustment member comprising an infrared absorption film arranged on a surface of at least the first light receiving electrode , and configured to make infrared reception sensitivity of the first light receiving electrode higher than that of the second light receiving electrode ; wherein the infrared detection device further comprises an optical element (OE); characterised in that the optical element is configured to direct light from a first infrared- detection target region (TGR1), set as a region targeting a first detection target, to the first light receiving electrode , wherein the first electrode is configured to receive light from the first infrared-detection target region (TGR1), and to direct light from a second infrared-detection target region (TGR2), set as a region targeting mainly a second detection target and part of the first detection target, to the second light receiving electrode wherein the second light receiving electrode is configured to receive light from the second infrared-detection target region (TGR2); and wherein the detection sensitivity is increased for the first infrared-detection target region (TGR1) and is reduced for the second infrared-detection target region (TGR2), such that the first detection target in the first infrared-detection target region is distinguished from the second detection target in the second infrared-detection target region. <EOS>