To provide a compact vibration reduction unit, a lens barrel, and a camera, which can perform positional detection with a high degree of accuracy during operations for vibration reduction. A vibration reduction unit of the present invention is comprising: a shooting optical system; a movable optical member that is part of the shooting optical system or which is another member, and which is provided movably relative to the shooting optical system; a magnetic sensor used to detect a position of the movable optical member; and a coil having a winding center line of a winding wire situated substantially in parallel with and on substantially the same plane as a given plane in which the magnetic sensor is disposed.