To reduce hysteresis torque in a lock-up device for a fluid type torque transmission device.

In this lock-up device 5, a retaining plate 52 is fixed to a piston 51 to hold a first torsion spring 54 in an elastically deformable manner in a rotating direction. In this case, a support plate 90 provided in a relatively rotatable manner to the retaining plate 52 has a cylindrical first support part 91 arranged on the radially outside of the first torsion spring 54 to abut on the radially outside portion of the first torsion spring 54.