To examine the effect of starch particle size on the digestibility and prebiotic effect of bolo, we conducted a feeding experiment on rats using bolo prepared with potato starch having different particle size distributions. The rats were fed a diet comprising bolo-like baked goods of small grain (S group), large grain (L group), unclassified (M group), and pregelatinized starch (α group) and an AIN-93G diet (AIN Group) for 14 days. The rats in the S, L, and M groups displayed similar physiological effects, such as enlarged cecum, decreased cecal content pH, increased fecal volume, and changes in the intestinal flora accompanied with a remarkable increase in the Bifidobacterium genus. However, no clear correlation was observed between starch particle size distribution and digestibility. These results indicate that the digestibility of the potato starch contained in bolo is influenced more by the crystalline structure of starch rather than its particle size. Thus, the bolo prepared with starch having different particle sizes contain resistant starch, are digested slowly, and have prebiotic effects.