Ginsenoside Rd was produced from ginsenoside Rc using a thermostable recombinant ${alpha}-{small{L}}$-arabinofuranosidase from Caldicellulosiruptor saccharolyticus. The optimal reaction conditions for the production of ginsenoside Rd from Rc were pH 5.5, $80^{circ}C$, 227 U enzyme/ml, and 8.0 g/l ginsenoside Rc in the presence of 30% (v/v) n-hexane. Under these conditions, the enzyme produced 7.0 g/l ginsenoside Rd after 30 min, with a molar yield of 100% and a productivity of 14 g $l^{-1};h^{-1}$. The conversion yield and productivity of ginsenoside Rd are the highest reported thus far among enzymatic transformations.