The utility model provides a labor-saving device for adjusting cable force of a bridge. The labor-saving device comprises a base, a supporting frame, a lower middle shaft, an upper middle shaft, a power chain wheel, a transmission chain wheel, a lower bearing, an upper bearing, a chain, a
crank, a winding disc and a counter-force
rope. The supporting frame is arranged on the base, the lower middle shaft is arranged at the lower end of the supporting frame, and the upper middle shaft is arranged at the upper end of the supporting frame. The lower bearing is sleeved on the lower middle shaft, and the upper bearing is sleeved on the upper middle shaft; the power chain wheel is rotationally arranged on the lower middle shaft through a lower bearing, and the transmission chain wheel is rotationally arranged on the upper middle shaft through an upper bearing; the power chain wheel and the transmission chain wheel are connected through a chain, and the
diameter of the transmission chain wheel is larger than that of the power chain wheel. A
crank is arranged in the middle of the front end of the power chain wheel, a winding disc is fixedly arranged in the middle of the front end of the transmission chain wheel, and one end of the counter-force
rope is fixed to a supporting frame at the rear end of the upper middle shaft. The device can realize single-person operation, and is convenient to operate, time-saving and labor-saving.