Approximately 50% of people in the world experience abdominal flatulence after the intake of foods containing galactosides such as lactose or soybean oligosaccharides. The galactoside hydrolyzing enzymes of ${alpha}$- and ${eta}$-galactosidases have been shown to reduce the levels of galactosides in both the food matrix and the human gastrointestinal tract. This study aimed to optimize the production of ${alpha}$- and ${eta}$-galactosidases of Bifidobacterium longum subsp. longum RD47 with a basal medium containing whey and corn steep liquor. The activities of both enzymes were determined after culturing at $37^{circ}C$ at pH 6.0 for 30 h. The optimal production of ${alpha}$- and ${eta}$-galactosidases was obtained with soybean oligosaccharides as a carbon source and proteose peptone no. 3 as a nitrogen source. The optimum pH for both ${alpha}$- and ${eta}$-galactosidases was 6.0. The optimum temperatures were $35^{circ}C$ for ${alpha}$-galactosidase and $37^{circ}C$ for ${eta}$-galactosidase. They showed temperature stability up to $37^{circ}C$. At a 1 mM concentration of metal ions, $CuSO_4$ inhibited the activities of ${alpha}$- and ${eta}$-galactosidases by 35% and 50%, respectively. On the basis of the results obtained in this study, B. longum RD47 may be used for the production of ${alpha}$- and ${eta}$-galactosidases, which may reduce the levels of flatulence factors.