A detector is provided by coating a fluid conductive material on a flat portion of a diaphragm. The detector includes: a resistor element; resistor element electrodes, which are overlapped and connected with mutually opposed parts of the resistor element; and a linear conductor connected with the resistor element electrodes. The resistor element electrodes each include: a linear portion having a linear inner side facing an inner side of paired one of the resistor element electrodes; and peripheral portions defined at both ends of the linear portion, at least one of the peripheral portions being connected with the linear conductor. All of the linear portions are arranged so that inner sides are arranged mutually in parallel. The resistor element is connected with the linear portion. The peripheral portions are exposed without being connected with the resistor element.