To provide a lock-up device and a fluid torque transmission device capable of improving responsiveness.

The lock-up device 5 of a torque converter 1 is provided with a piston 53, a first friction plate 51, a second friction plate 52, and a damper mechanism 6. The piston 53 is provided rotatably and movably in an axial direction with respect to a turbine 4. The first friction plate 51 is provided to integrally rotate and movably in an axial direction with respect to a front cover 2. The second friction plate 52 is provided to integrally rotate and to relatively move in an axial direction with respect to the piston 53. The damper mechanism 6 resiliently connects the second friction plate 52 and the turbine 4 in a rotating direction.