DYNAMIC DAMPER DEVICE

A dynamic damper device (1) includes a variable inertial mass device (20) that variably controls inertial mass of a damper mass (21), an elastic body (31) that connects a rotary shaft (10) rotated by power transmitted thereto and an input member (21C) of the variable inertial mass device (20), and a variable damping force device (40) that variably controls a damping force to the elastic body (31). Accordingly, the dynamic damper devices (1) have the advantageous effect that vibrations can be appropriately reduced.