To reduce a manufacturing cost, in a lock-up device of a hydraulic type torque transmission device.

The lock-up device 1 is used for a torque converter 1 disposed between an engine and a transmission to transmit torque from an input rotary member and absorb and damp torsion vibration. The lock-up device 1 has a piston 71, a driven plate 73, a plurality of large torsion springs 74, and a support member 76, and a retaining plate 72. The piston 71 is rotatably and axially supported to be movable, with respect to the input rotary member. The large torsion springs 74 are elastically connects the piston 71 with the driven plate 73 in a rotational direction. The support member 76 has an outer peripheral side support part 76a supporting an outer peripheral side of the large torsion spring 74. The retaining plate 72 has a fixed part 72a fixed to the piston 71, and an outer peripheral side projection part 72c radially supporting the outer peripheral side support part 76a.