To provide an infrared detection device and its manufacturing method which improves remarkably infrared detection sensitivity by suppressing heat dissipation from an infrared detection part.

This infrared detection device is constituted of the infrared detection part 31 including a sensor layer 21 for detecting a temperature change caused by infrared incidence, a pair of support legs 32, 33 for supporting in midair the infrared detection part 31, a pair of first electrode layers 22, 23 connected electrically to the sensor layer 21, and second electrode layers 26a 27a arranged on a substrate part 34 separately from the first electrode layers 22, 23 and capacitively coupled respectively with the first electrode layers 22, 23, or the like.