A vibration damping device 20 includes: a crank member 22 that is coupled to a driven member 15 via a first coupling shaft A1 and that is swingable about the first coupling shaft A1 along with rotation of the driven member 15; and an inertial mass body 24 that is coupled to the driven member 15 via the crank member 22 and a connecting rod 23 and that is swung about a center of rotation RC in conjunction with the crank member 22 along with rotation of the driven member 15. A component force of a centrifugal force that acts on the crank member 22 along with rotation of the driven member 15 in a direction that is orthogonal to the direction from the center of the first coupling shaft A1 toward the center of gravity G always acts on the crank member 22 as a restoring force that acts to return the inertial mass body 24 to the center of the swing range. The component force is maximum when the inertial mass body 24 is positioned at the center of the swing range.