An infrared sensor is formed with a first infrared detecting element for infrared detection disposed in a container through a supporting substrate, and a second infrared detecting element for temperature compensation also disposed in the container to be shielded by the supporting substrate of the first infrared detecting element from incident infrared within the container, while a temperature sensing section of the first infrared detecting element is born in non-contacting state with respect to a supporting part of the substrate for the element, whereby the sensitivity can be remarkably improved with a simpler arrangement while keeping a high precision and inexpensiveness.