A variable damper includes a first plate connected to a first rotating shaft and a second plate connected to a second rotating shaft. A damper spring transmits power between the first and second plates, and a variable friction apparatus regulates a frictional force between the first and second plates. The variable friction apparatus includes a solenoid coil, a solenoid pawl, a pressure plate with a slanted surface, a friction plate between the pressure plate and the second plate, a wedge contacting the pressure plate and movable along the slanted surface in response to the state of the solenoid pawl, and a wedge spring supporting the wedge.