To provide an infrared detecting element where an infrared detection property is kept to be favorable by improving an infrared absorption rate of an infrared absorption membrane even if the thickness of the infrared absorption membrane formed on a membrane is ≥3μm.

In the infrared detecting element having the membrane formed on a diaphragm structure of a silicon substrate and the infrared absorption layer composed of an evaporative deposition object of metallic particles formed on the membrane, the infrared absorption layer has a first metallic black membrane formed on the surface of the membrane and a second metallic black membrane formed on the first metallic black membrane. In the first metallic black membrane, infrared transmission is lower and a reflection factor is higher than those in the second metallic black membrane.

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