A damper device including an input element and an output element; an elastic body transmitting torque between the input element and the output element; and a rotary inertia mass damper having a mass body. The rotary inertia mass damper includes a sun gear, a carrier rotatably supporting pinion gears, and a ring gear that meshes with the pinion gears and serving as the mass body. A pair of washers is located on both sides of each pinion gear axially. The ring gear includes an annulus gear having internal teeth meshing with the pinion gears and a weight body fixed to the annulus gear such that the weight body is in contact with a side surface of the annulus gear. An inner circumferential surface of the weight body is supported in a radial direction by a tip of the pinion gear or an outer circumferential surface of the washer.