In this damper mechanism, when small fluctuations in torque input to the damper mechanism occur, small hysteresis torque is produced as a result of pressure contact between a radial plate and a first friction section. Consequently, the small torque fluctuations can be damped between the radial plate and the first friction region of the damper mechanism and can be output to an input shaft. In addition, along the direction of relative rotation of an annular plate and the radial plate, the friction coefficients of the annular plate and the radial plate become larger as the torsion angles of both plates become larger. Therefore, even when torque fluctuations become large, the hysteresis torque can be produced in accordance with the magnitude of the torque fluctuations.