A liquid level detecting device includes a resistor plate having conductive segments, a float that vertically moves in accordance with a displacement of a liquid level, a float arm that has one end to which the float is attached and the other end which is rotatably supported so as to be rotated in association with a vertical movement of the float, and a contact point that slides on the conductive segments in association with a rotation of the float arm. Each of the conductive segments is formed of a first metallic material and a second metallic material. The first metallic material has silver (Ag) and palladium (Pd) and the second metallic material has gold (Au) as a main component. A part which is to be brought into contact with the contact point in each of the conductive segments is formed of the second metallic material.