A sensor board, comprising: an insulating substrate having an upper surface and a lower surface; a first detection electrode located on the upper surface of the insulating substrate; a second detection electrode located on the lower surface of the insulating substrate; and a heat generator located between the first detection electrode and the second detection electrode inside the insulating substrate, the heat generator including an upper conductor layer located adjacent to the first detection electrode and below the upper surface of the insulating substrate, and a lower conductor layer located adjacent to the second detection electrode and above the lower surface of the insulating substrate, wherein the upper conductor layer and the lower conductor layer are located at a periphery of the insulating substrate in a plan view, and wherein the heat generator includes a connection section and terminals for each of the upper conductor layer and the lower conductor layer, wherein a portion of the insulating substrate between the upper conductor layer and the upper surface of the insulating substrate has a same thickness as a portion of the insulating substrate between the lower conductor layer and the lower surface of the insulating substrate, wherein the first detection electrode and the second detection electrode are columnar, wherein the first detection electrode includes adjacent positive and negative electrodes (2a, 2b) and the second detection electrode includes adjacent positive and negative electrodes (3a, 3b), wherein the positive electrodes (2a, 3a) are connected to a terminal through wiring conductors such that they are configured to be connected to a positive electrode of a DC power source and the negative electrodes (2b, 3b) are connected to another terminal through wiring conductors such that they are configured to be connected to a negative electrode of the DC power source, wherein the first detection electrode and the second detection electrode are feedthrough conductors that partially extend through the insulating substrate in a thickness direction, wherein, when viewed in a cross-section along the thickness direction, the upper conductor layer overlaps the first detection electrode and the lower conductor layer overlaps the second detection electrode, wherein end faces of the feedthrough conductors are exposed at the upper and lower surfaces of the insulating substrate, and wherein the upper and lower conductor layers are located without overlapping the first detection electrode or the second detection electrode in a plan view. an insulating substrate having an upper surface and a lower surface; a first detection electrode located on the upper surface of the insulating substrate; a second detection electrode located on the lower surface of the insulating substrate; and a heat generator located between the first detection electrode and the second detection electrode inside the insulating substrate, the heat generator including an upper conductor layer located adjacent to the first detection electrode and below the upper surface of the insulating substrate, and a lower conductor layer located adjacent to the second detection electrode and above the lower surface of the insulating substrate, wherein the upper conductor layer and the lower conductor layer are located at a periphery of the insulating substrate in a plan view, and wherein the heat generator includes a connection section and terminals for each of the upper conductor layer and the lower conductor layer, wherein a portion of the insulating substrate between the upper conductor layer and the upper surface of the insulating substrate has a same thickness as a portion of the insulating substrate between the lower conductor layer and the lower surface of the insulating substrate, wherein the first detection electrode and the second detection electrode are columnar, wherein the first detection electrode includes adjacent positive and negative electrodes (2a, 2b) and the second detection electrode includes adjacent positive and negative electrodes (3a, 3b), wherein the positive electrodes (2a, 3a) are connected to a terminal through wiring conductors such that they are configured to be connected to a positive electrode of a DC power source and the negative electrodes (2b, 3b) are connected to another terminal through wiring conductors such that they are configured to be connected to a negative electrode of the DC power source, wherein the first detection electrode and the second detection electrode are feedthrough conductors that partially extend through the insulating substrate in a thickness direction, wherein, when viewed in a cross-section along the thickness direction, the upper conductor layer overlaps the first detection electrode and the lower conductor layer overlaps the second detection electrode, wherein end faces of the feedthrough conductors are exposed at the upper and lower surfaces of the insulating substrate, and wherein the upper and lower conductor layers are located without overlapping the first detection electrode or the second detection electrode in a plan view.