Rotary input device and a rotation detecting apparatus using the same

Regardless of the surrounding environment, correct rotation direction, for detecting a rotation angle. The first and the equally-spaced electrode holding plate 52 having equally-spaced electrodes 56 along the circumference of a circle, the first circle opposite to the second a-phase electrodes α number of which are arranged along the circumference of a circle and a β-number of b-phase electrode and the phase electrode holding plate 64 which is fixed having an, if α is 2 or more, any two of a-phase electrodes, rotating on a second circumference of a circle to each other in positions displaced an angle of an integral multiple of 2 [pi / N in the direction. If β is 2 or more, any two b-phase electrodes, is in the positions displaced an angle of an integral multiple of the rotational direction 2 [pi / N on a second circumference of a circle with one another. b-phase to a-phase electrodes electrodes are an integer multiple of the angular displacement position and a not so as not to phase electrode of the second rotational direction [pi / N on the circumference of a circle each other.