There is provided a liquid level detecting apparatus capable of achieving miniaturization, which includes a float arm 2 provided with a float floating on a liquid surface, an arm holder 4 for holding the float arm 2 and provided with shaft portions 24 as rotation supporting points of the float arm 2, a main body frame 3 provided with two bearing portions 30 and 31 for axially supporting the shaft portions 24 of the arm holder 4, a circuit board 7 fixed to the main body frame 3, and a contact holding member 5 provided with a sliding contact 6 sliding on the circuit board 7 and fixed to the arm holder 4, and the arm holder 4 is positioned between the bearing portions 30 and 31 and holds the float arm 2 and the contact holding member 5.