Gastric digestion is the major digestion process in humans and is strongly affected by both physical and chemical digestion. In vitro approaches using different gastric digestion models have received a great deal of attention in several scientific and industrial fields, including food science and technology, due to experiments being conducted under various conditions and with better reproducibility of the experiment data. The development of simple in vitro gastric digestion devices that enable quantitative consideration of the influence of gastric peristalsis has been necessary for simulating and analyzing the disintegration of solid foods in the stomach. The authors and co-workers recently developed a human gastric digestion simulator (GDS) that simplifies the antrum geometry, is capable of simulated gastric peristalsis, and which enables direct observation of the disintegration of food particles in the gastric contents. This article provides a brief overview of our findings regarding the GDS. First, the concept and development of the GDS is introduced. The disintegration characteristics of representative (model) foods using the GDS are described next, providing insights into the digestion processes influenced by gastric peristalsis. After further improvement, the GDS is expected to offer potential as a tool for designing novel nutraceutical and functional foods for which digestibility is well controlled.