Provided is an infrared sensor which is capable of measuring a temperature of an object to be measured with high accuracy even when lead wires are connected to one side thereof. The infrared sensor includes an insulating film; a first and a second heat sensitive element which are provided on one face of the insulating film; a first and a second wiring film that are respectively connected to the first and the second heat sensitive element; an infrared reflecting film; a plurality of terminal electrodes; and a thermal resistance adjusting film which is provided on the other face of the insulating film, is in opposition to at least a portion of the longer one of the first or the second wiring film in wiring distance from the terminal electrodes, and is formed of a material with greater heat dissipation than the insulating film.