A ski-lift seat return device having a supporting structure; a reel mounted to rotate about an axis with respect to the supporting structure; a cable wound about the reel; a spring mechanism for opposing unwinding of the cable, and for rewinding the cable unwound off the reel; and a contactless magnetic brake connected to the reel and the supporting structure to adjust the brake torque as a function of the rotation speed of the reel; and wherein the magnetic brake has a first wall integral with and preferably defining part of the supporting structure; and a second wall connected movably to the reel and moved towards the first wall by the rotation speed of the reel; the first and second wall being coupled magnetically to each other.