1. A failure detection system used in a manufacturing line of absorbent articles, the manufacturing line having a plurality of processing steps for a conveyed continuous web, the failure detection system comprising: an image processing unit for acquiring morphological images illustrating morphologies of entire ones of the absorbent articles after processing of the absorbent articles in each of the said processing steps; a failure detection unit that detects the existence of a failure location of the absorbent articles after processing, based on the morphological images acquired by the image processing unit; and an image display unit that displays images of the absorbent articles after processing, when a failure location of an absorbent article is detected by the failure detection unit, wherein the failure detection unit determines if a processing step has caused a processing failure by comparing subsequent acquired morphological images of a processed absorbent article with precedingly obtained morphological images of the processed absorbent article.