A lens module includes a lens barrel, a first lens, an adjusting disk and at least one first elastic member. The first lens has at least three first sloping portions thereon each having a lower end and a higher end gradually sloping from the lower end. The first sloping portions arranged end to end with the higher end of each first sloping portion being adjacent to the lower end of the corresponding adjacent first sloping portion, with the first sloping portions arranged on a common circular path. The adjusting disk has a first surface and an opposite second surface. The adjusting disk is rotatably mounted on the lens barrel. The adjusting disk has at least three first protrusions on the first surface thereof. The first protrusions respectively abut the first sloping portions of the first lens. The first elastic member biases the first lens toward the adjusting disk.