In order to reduce the dimensions of a lockup device in the axial direction and enable the overall space occupied by a torque converter in the axial direction to be made compact, and to reduce the number of parts, this lockup device is equipped with a piston (10), first and second plates (11, 12), and multiple outer circumferential and inner circumferential torsion springs (14, 15). The piston (10) presses friction members (19), which are affixed to a side surface of the piston (10), against a front cover (2), or releases this compression. Furthermore, the piston (10) has multiple engaging parts (10c) formed with a portion thereof bent towards a turbine. The second plate (12) is coupled to the turbine. The outer circumferential torsion springs (14) are arranged between the piston (10) and the first plate (11) with the ends in the circumferential direction engaging the engaging parts (10c) of the piston (10), and torque is transmitted from the piston (10) toward the first plate (11).