A nutrition-enriched rice manufacturing method includes a harvesting process of harvesting raw unhulled rice as a starting material from a paddy field, a nutrition enriching process of generating nutrition-enriched unhulled rice by heating the raw unhulled rice of which average moisture content is at a predetermined level of 20% by weight or more with a microwave heating device and heat-retaining the raw unhulled rice for a predetermined period of time with a heat retention device, and a drying, hulling and polishing process of drying nutrition-enriched unhulled rice so as to have an average moisture content suitable to a long-term storage, hulling to remove chaff, and polishing to remove embryo and bran layer so as to obtain nutrition-enriched polished rice which abundantly contains gamma aminobutyric acid in an endosperm part.
