The experiment was carried out in order to investigate the development of vascular bundles and air spaces of rice internode, and its relationships to the panicle characteristics of rice varieties. The results obtained were as follows; The number of total vascular bundles in upper 1st internode was significantly different among varieties, but there was no remarkable differences among varieties and nodal positions below the 2nd internode. In the 5th internode 21-31 air spaces according to varieties was developed, however, no air space was found in upper 1st and 2nd internodes at maturing stage. Significant varietal difference of air space was observed in upper 4th internode. The number of vascular bundles, internodal thickness were positively correlated with panicle length, the number of rachis branches, and the spikelets in rice varieties.