To provide a non-contact type potentiometer adapting to many turns without limitation and having high resolution in rotation amount detection.

This potentiometer is equipped with first shafts 100 and 112a endlessly rotatable, first detection means 114a and 116a for magnetically detecting rotation angles of the first shafts in a non-contacting manner, a second shaft 112b endlessly rotatable, second detection means 114b and 116b for magnetically detecting a rotation angle of the second shaft in a non-contacting manner, a transmission means 400 for reducing the rotation of the first shaft to transmit it to the second shaft, and an output means 602 for outputting an electrical signal proportional to the rotation amount of the first shafts based on detection signals of the first and second detection means.