To provide a wheelchair lifting device capable of detecting the winding amount of a belt without using a rotation detecting plate.

A belt 33 for lifting a wheelchair is provided with a plurality of reflection parts 51 and the respective reflection parts 51 are arranged at equal intervals in the length direction of the belt 33. Thus, a detection area 54 is set by alternately forming the high reflection areas 52 of high light reflectance and the low reflection areas 53 of low light reflectance. A detection sensor 71 is provided with a light emitting part 82 for emitting detection light 81, a light receiving part 84 for receiving reflected light 83, and a control circuit. The light receiving part 84 outputs the electric signals of a voltage corresponding to the intensity of the reflected light 83 to the control circuit, and the control circuit outputs output signals 85 composed of "H" signals or "L" signals according to an input voltage from the light receiving part 84. The light emitting part 82 projects the detection light 81 to the detection area 54, and the light receiving part 84 receives reflected light 83 reflected in the detection area 54.