A low-noise lifting device includes a rack and a gear. The rack includes first teeth each having a first crown portion. A surface of the first crown portion is defined as a first contact surface having a circular arc shape. The gear includes second teeth. A second root portion is defined between every adjacent two of the second teeth. A surface of the second root portion is defined as a second contact surface having a circular arc shape. When the gear is meshed with the rack, the second contact surface and the first contact surface are in close contact with each other in a circular arc shape, without a backlash, so as to reduce the noise generated by the transmission.