A light-channeling apparatus for a scanning module comprises a first light-guiding tube, a second light-guiding tube, and a collimating lens positioned inside the first light-guiding tube. The first and second light-guiding tubes are attached to a body casing of the scanning module. The scanning module uses the first light-guiding tube having the collimating lens to channel light from a light source to a scanning region and uses the second light-guiding tube to channel light reflected from the scanning region to a light passage slit on the body casing, to minimize dispersion of light from the light source and keep external light out of the light transmission pathway.