ARF6 has been shown to be involved in the membrane dynamics and actin re-organization. ARF6 is made into its active form by conversion from ARF-ADP to ARF-ATP, and this conversion is madiated by EFA6 which is composed of multiple isoforms. The present study was attempted to investigate the localization of EFA6D in the submandibular gland, with an aim to clarify more our knowledge about how the membrane dynamics is involved in the regulation of production and secretion of saliva in the acinus and various segments of the distal and proximal ducts in immunohistochemistry. Intense immunoreactivity for EFA6D was localized in some, but not all, ductal epithelial cells of the distal and proximal ducts. The immunopositive cells were a few in the intercalated ducts and the proximal excretory ducts, while they were numerous in the granular and striated portions of the distal ducts, where the immunopositive cells were randomly located within the epithelia, and the immuno-intensity was variable among them. The immunoreactivity appeared in granular forms, which were distributed throughout the basal cytoplasm without shift to basolateral or apical cytoplasm. No intense immunoreactivity was discerned in the acinar epithelial cells. The present finding indicates the high heterogeneity in the activity of EFA6-ARF6-signaling involved in the membrane dynamics among the ductal epithelial cells along the distal to proximal excretory duct of the salivary gland.