In preparing a glycoside compound from (a) a furanose compound or pyranose compound, and (b) an alcohol compound, a process for preparing a glycoside compound in which glycosidic bond locates selectively trans form relative to C-2 hydroxyl group, the process comprising using a furanose compound wherein the hydroxyl at the 2-position may have a substituent protected with a group A, or a pyranose compound which may have a substituentwherein R2 and R3 are the same or different and are each alkyl having 1 to 4 carbon atoms or aryl having or not having a substituent, or R2 and R3 are combined to form alkylene having 2 to 4 carbon atoms (the alkylene may be substituted with alkyl having 1 to 4 carbon atoms, or may have intervening phenylene), and m and n are each an integer of 0 or 1.
