Low-glutelin rice has low content of digestible protein glutelin, and is expected to use as raw material for sake brewing. To characterize endosperm cell structure of low-glutelin rice, the storage proteins of endosperm cells in polished rice (degree of milling, 70%; used as raw material for sake brewing) of two low-glutelin rice varieties, LGC1 and Tashu-kei 1001, and two general rice cultivars (brewer's rice), Hyogokitanishiki and Yamadanishiki, were observed using a transmission electron microscope. Low-glutelin rice differed from general rice cultivars in the composition of major storage proteins and the transgranular distribution of storage proteins as well as in the distribution of protein bodies in endosperm cells. Furthermore, low-glutelin rice had a specific endosperm cell structure containing many type I protein bodies even in the outer layer of polished rice grains.