Diabetes mellitus (DM) is a currently arising disease with patients increasing throughout the world. Treaments of diabetes mellitus focus on control of blood glucose level. In late years, some of flavonoid glycosides are reported as an insulin-mimetic compound which regulates glucose uptake ability of insulin-sensitive cells (insulin-mimetic activity). These compounds are thought to be effective for the treatment of DM by replacing insulin or supporting currently used medicines. One of these insulin-mimetic flavonoid glycosides, kaempferol 3-O-neohesperidoside (1), was idolated from a stem of Cyathea phalerata Mart., and reported to show strong insulin-mimetic activity at nanomolar level. We focused on this attractive compound, and started to perform a structure-activity relationship study on the insulin-mimetic effect of 1 by a synthetic method and in vitro assay emloying cultured cells. We achieved a synthesis of 1 for the first time, and performed insluin-mimetic activity examination of synthetic 1 against muscular cell model. L6 cells. As a result, a significantly high activity was observed in synthetic 1 at 1 nM. Further study on structure-activity relationship using several synthetic derivatives with partial structure of 1 revealed that neohesperidose (19) to be the major contributing structure for this activity. These findings may lead to utilization of disacchrides for treatment for diabetes mellitus.