A rotary capacitor which changes electrostatic capacity by changing a mutually opposite area of a pair of electrodes which opposes each other, includes a rotary shaft which can rotate around a central axis, wherein the pair of electrodes includes a first electrode plate which protrudes from a circumferential surface of the rotary shaft, and a second electrode plate which may be separated in a direction along the central axis with respect to the first electrode plate and may be disposed so as to oppose the first electrode plate, and a notch which penetrates in a plate thickness direction may be formed on an edge portion of the first electrode plate.