A damper device comprising: a coil spring (31, 32) interposed in a circumferential direction between a first rotating body and a second rotating body, in which two ends thereof are supported to the rotating bodies (1, 2), orienting a direction along a spring central axis (Sc), which is a center of winding, toward the circumferential direction; and a spring seat (41, 42) made of resin, having a metallic core member inside, which is attached to the rotating bodies (1, 2), in a state in which the two ends of the coil spring (31, 32) are supported in the direction along the spring central axis; wherein the spring seat (41, 42) comprises a seat portion on which the ends of the coil springs (31, 32) are seated in the direction along the spring central axis (Sc), and an overhang portion which is extended from an outer diameter direction end of the rotating body in the seat portion in the circumferential direction and covers the outer diameter direction of the coil spring (31, 32), and the metallic core member comprises an overhang portion metallic core member which is extended from the overhang portion at an outer diameter direction position on the spring central axis (Sc), and the overhang portion metallic core member comprises a low-rigidity portion that is provided on a side close to the seat portion in the circumferential direction with a relatively lower rigidity, and a high-rigidity portion that is provided on a side far from the seat portion in the circumferential direction with a relatively higher rigidity, characterized in that, the overhang portion metallic core member has a shape that gradually widens from the low-rigidity portion toward a distal end of the high-rigidity portion. a coil spring (31, 32) interposed in a circumferential direction between a first rotating body and a second rotating body, in which two ends thereof are supported to the rotating bodies (1, 2), orienting a direction along a spring central axis (Sc), which is a center of winding, toward the circumferential direction; and a spring seat (41, 42) made of resin, having a metallic core member inside, which is attached to the rotating bodies (1, 2), in a state in which the two ends of the coil spring (31, 32) are supported in the direction along the spring central axis; wherein the spring seat (41, 42) comprises a seat portion on which the ends of the coil springs (31, 32) are seated in the direction along the spring central axis (Sc), and an overhang portion which is extended from an outer diameter direction end of the rotating body in the seat portion in the circumferential direction and covers the outer diameter direction of the coil spring (31, 32), and the metallic core member comprises an overhang portion metallic core member which is extended from the overhang portion at an outer diameter direction position on the spring central axis (Sc), and the overhang portion metallic core member comprises a low-rigidity portion that is provided on a side close to the seat portion in the circumferential direction with a relatively lower rigidity, and a high-rigidity portion that is provided on a side far from the seat portion in the circumferential direction with a relatively higher rigidity, characterized in that, the overhang portion metallic core member has a shape that gradually widens from the low-rigidity portion toward a distal end of the high-rigidity portion.