An infrared sensor chip (3; 31), comprising: a supporting substrate having a cavity; at least one bridge section extending directly above the cavity and having at least one end supported by the supporting substrate and an other end, and a thermopile wiring formed in the at least one bridge section, the thermopile wiring including hot junctions and cold junctions, the hot junctions being connected to the cold junctions, the hot junctions being provided in the at least one bridge section, the cold junctions being provided directly above the supporting substrate, the at least one bridge section being provided with: at least one breakage detection wiring for detecting breakage of the at least one bridge section; and at least one heater wiring (22; 32), the at least one breakage detection wiring being wired along the thermopile wiring, the at least one heater wiring (22; 32) being wired such that part of the at least one heater wiring (22; 32) is in an area between the other end of the at least one bridge section and the hot junctions, wherein the at least one breakage detection wiring includes two first wiring sections extending in a first direction in which the at least one end and the other end are aligned and a second wiring section having both ends connected to ends of the two first wiring sections at the other end, the at least one heater wiring (22; 32) includes a lead line section wired outside the area and having an end in the area and a heater section connected to an end of the lead line section and wired in the area, wherein the heater section is made of polysilicon, characterized in that the lead line section is made of metal. a supporting substrate having a cavity; at least one bridge section extending directly above the cavity and having at least one end supported by the supporting substrate and an other end, and a thermopile wiring formed in the at least one bridge section, the thermopile wiring including hot junctions and cold junctions, the hot junctions being connected to the cold junctions, the hot junctions being provided in the at least one bridge section, the cold junctions being provided directly above the supporting substrate, the at least one bridge section being provided with: at least one breakage detection wiring for detecting breakage of the at least one bridge section; and at least one heater wiring (22; 32), the at least one breakage detection wiring being wired along the thermopile wiring, the at least one heater wiring (22; 32) being wired such that part of the at least one heater wiring (22; 32) is in an area between the other end of the at least one bridge section and the hot junctions, wherein the at least one breakage detection wiring includes two first wiring sections extending in a first direction in which the at least one end and the other end are aligned and a second wiring section having both ends connected to ends of the two first wiring sections at the other end, two first wiring sections extending in a first direction in which the at least one end and the other end are aligned and a second wiring section having both ends connected to ends of the two first wiring sections at the other end, the at least one heater wiring (22; 32) includes a lead line section wired outside the area and having an end in the area and a heater section connected to an end of the lead line section and wired in the area, wherein a lead line section wired outside the area and having an end in the area and a heater section connected to an end of the lead line section and wired in the area, wherein the heater section is made of polysilicon,