An infrared sensor (1, 21) comprising: an insulating film; a pair of first terminal electrodes and a pair of second terminal electrodes that are formed by patterning on one surface of the insulating film; a first heat sensitive element and a second heat sensitive element that are provided on the one surface of the insulating film; a pair of first pattern wirings that are formed by patterning on the one surface of the insulating film with one ends thereof being connected to the first heat sensitive element and the other ends thereof being connected to the pair of first terminal electrodes; a pair of second pattern wirings (6B, 26B) that are formed by patterning on the one surface of the insulating film with one ends thereof being connected to the second heat sensitive element and the other ends thereof being connected to the pair of second terminal electrodes; a light receiving region that is provided on the other surface of the insulating film and faces the first heat sensitive element; and an infrared reflection film (8, 28) formed on the other surface of the insulating film so as to cover at least a region facing the second heat sensitive element while avoiding the light receiving region, wherein the infrared reflection film (8, 28) expands around the region facing the second heat sensitive element while avoiding a region facing the pair of second pattern wirings (6B, 26B), and wherein cut portions are respectively formed in regions of the infrared reflection film (8, 28) facing the pair of second pattern wirings (6B, 26B) such that the infrared reflection film (8, 28) is partially removed. an insulating film; a pair of first terminal electrodes and a pair of second terminal electrodes that are formed by patterning on one surface of the insulating film; a first heat sensitive element and a second heat sensitive element that are provided on the one surface of the insulating film; a pair of first pattern wirings that are formed by patterning on the one surface of the insulating film with one ends thereof being connected to the first heat sensitive element and the other ends thereof being connected to the pair of first terminal electrodes; a pair of second pattern wirings (6B, 26B) that are formed by patterning on the one surface of the insulating film with one ends thereof being connected to the second heat sensitive element and the other ends thereof being connected to the pair of second terminal electrodes; a light receiving region that is provided on the other surface of the insulating film and faces the first heat sensitive element; and an infrared reflection film (8, 28) formed on the other surface of the insulating film so as to cover at least a region facing the second heat sensitive element while avoiding the light receiving region, wherein the infrared reflection film (8, 28) expands around the region facing the second heat sensitive element while avoiding a region facing the pair of second pattern wirings (6B, 26B), and wherein cut portions are respectively formed in regions of the infrared reflection film (8, 28) facing the pair of second pattern wirings (6B, 26B) such that the infrared reflection film (8, 28) is partially removed.