To provide an inclination sensor capable of miniaturizing a case body as much as possible, and detecting accurately the inclination state even when the case body is constituted in the miniaturized state.

This sensor is equipped with a rotating member 2 constituted in an approximately U-shaped state and having a deadweight part 22 and a magnet part 21, the case body 1 for storing the rotating member 2 in an inside space S, and one magnetic detection member 3 having one magnetic flux detection area V on the circumference of a rotating shaft of the rotating member 2. In the sensor wherein the magnet part 21 is rotated relatively by tilting the case body 1 and the inclination state of the case body 1 is detected by the magnetic detection member 3, the rotating shaft of the rotating member 2 is provided on the center of the inside space in the case body 1, and a plurality of magnet parts 21 are provided independently on the circumference of the rotating shaft of the rotating member 2. The magnet parts 21 are provided by polarizing both ends of the rotating member 2 constituted of a magnetic body.