Fuel property sensor

A fuel property sensor comprising:

• a housing defining a fuel chamber in which a fuel passes;
• a pair of first and second electrodes arranged in the fuel chamber to measure an electric capacitance therebetween so as to detect a mixing ratio of alcohol to gasoline in the fuel, the first electrode being located such that an outer wall surface of the first electrode is exposed in the fuel;
• a sensing portion contacting an inner wall surface of the first electrode, to detect a temperature of the liquid fluid via the first electrode;
• a lead configured to support the sensing portion, the lead having one end portion connected to the sensing portion and the other end portion connected to a plate portion attached to the housing;
• and
• an elastic deformation portion provided as a part of the lead,
• wherein the elastic deformation portion is configured to be elastically deformed and to cause the sensing portion to be biased in a direction on which the sensing portion contacts the inner wall surface of the first electrode.