A sensor housing of a fluid level sensor includes a peripheral wall portion and a lead wire inserting portion. The peripheral wall portion forms a hollow space penetrating in the depth direction of the sensor housing and is formed in a manner of surrounding the periphery of a terminal area of a lead frame. The lead wire inserting portion is formed by notching the peripheral wall portion in the depth direction of the sensor housing. The lead wire inserting portion consists of a first inserting portion into which a lead wire extending from the terminal area is inserted and a second inserting portion into which the lead wire is inserted after passing through the first inserting portion and holds the lead wire in a manner of bending the lead wire in a crank shape. With this configuration, the fluid level sensor can prevent leak current generated on the terminal area and thus can connect a conductive wire (the lead wire) used for connection with an external circuit with the terminal area in good condition.