Taxifolin-3-O-$eta$-D-xylopyranoside and quercetin-3-O-$alpha$-L-rhamnopyranoside were isolated from an EtOAc-soluble extract of the leaves of Chamaecyparis obtuse. Quercetin-3-O-$alpha$-L-rhamnopyranoside was found to possess a potent inhibitory activity of human recombinant aldose reductase in vitro, its $IC_{50}$ value being $11.5;{mu}M$. Kinetic analysis showed that quercetin-3-O-$alpha$-L-rhamnopyranoside exhibited uncompetitive inhibition against DL-glyceraldehyde. Also, quercetin-3-O-$alpha$-L-rhamnopyranoside suppresses sorbitol accumulation in rat lens under high glucose conditions, demonstrating the potential to prevent sorbitol accumulation in vivo. These results suggest that this compound may be a promising agent in the prevention or treatment of diabetic complications.