To provide a position detector that can be made thin with a simple structure. A position detector 100 having an operation knob 1 supported rotatably and detecting the operation position of the operation knob 1 includes a movable body 3 which rotates with the rotating operation of the operation knob 1 and having one end serving as a movable electrode 5, an insulating substrate 11, a fixed electrode 7 formed on the insulating substrate 11, and arranged in non-contact with the movable electrode 5, and a capacitance sensor 9 for detecting the capacitance C generated between the movable electrode 5 and fixed electrode 7. Operation position of the operation knob 1 is detected by the magnitude of the capacitance C.