The effect of Benitenshi sweet potatoes on defecation and gut microbiota was examined in 22 female university students. The study included 4 experimental periods and lasted 4 weeks. The first week was the control period; the students consumed 300 g, 0 g, and 100 g of Benitenshi during the 2nd, 3rd, and 4th weeks, respectively. Dietary fiber in peeled Benitenshi was estimated to be 2.9 g per 100 g after heat-treatment at 200-210℃ for 1 hour. Fecal weight was measured in comparison to a wood cube. Subjetive bowel condition and abdominal distention were assessed using 4-score questionnaires. For measurement of microbiota, fresh fecal samples were collected on the last day of each experimental period. Gut microbiota was analyzed by terminal restriction fragment length polymorphism (T-RFLP) . The results showed that fecal weight was 1.6 times higher after ingestion of 300 g of Benitenshi and 1.5 times higher after ingestion of 100 g, compared with the control period. Defecation frequency was also significantly increased after intakes of 300 g compared with intake during the control period. Bowel condition and ease of defecation were improved with an intake of 300 g, and abdominal distention did not change. In addition, increased Benitenshi intake significantly increased the levels of the operational taxonomic unit, A58, which contained Faecalibacterium sp. These findings suggest that Benitenshi intake might improve bowel condition and gut microbiota without abdominal distention.