A temperature sensor supporting device includes a supporting body having first and second groove portions, a separation preventive part, and a pair of harnesses connected to a temperature sensor. The first groove portion is set to have such a groove width size as to permit clamping of proximal end parts of the harnesses inward of the supporting body when the proximal end parts are viewed as a single overlapping line from a first angle. The second groove portion is set to have such a groove width size as to permit clamping of intermediate parts of the harnesses inward of the supporting body when the intermediate parts are viewed as two lines from a second angle. The proximal end parts and the intermediate parts are clamped respectively in the first and second groove portions so that the sensor is positioned and fixed with the sensor disposed outside the supporting body.