1. An appearance inspection apparatus comprising: an aligning and conveying device having an aligning and conveying member with one or a plurality of conveying passages, and a vibration exciter for alignment for applying a vibration to the aligning and conveying member, the aligning and conveying device for advancing inspection objects placed on the aligning and conveying member in the conveying passages by applying a vibration to them, and for, in each of the conveying passages, aligning the inspection objects in a row and conveying them; a slide-down mechanism having slide-down passages which are separately connected to the respective conveying passages of the aligning and conveying member for allowing the inspection object to freely slide down therein, and which are provided being tilted downward with respect to extensions of the conveying passages; an imaging device disposed in the vicinity of the slide-down passages for imaging upper surfaces of the inspection objects sliding down in the slide-down passages; and a sorting device for analyzing the images of the inspection objects which are captured by the imaging device, judging the qualities of the upper surfaces of the inspection objects, and sorting the inspection objects sliding down in the slide-down passages on the basis of the judgment results, wherein the slide-down mechanism has an angle adjustment part for adjusting a tilt angle of the slide-down passages.