A lock-up device includes a piston, a drive plate, a plurality of radial outer side torsion springs, a float member, a driven plate, a plurality of radial inner side torsion springs and an intermediate member. The float member is configured to rotate relative to the drive plate, to cause the first and second radial outer side elastic members to act in series. The intermediate member is configured to rotate relative to the drive plate and the driven plate, and to transmit the torque from the first and second radial outer side elastic members to the first and second radial inner side elastic members.