More specifically, the present invention provides 2-substituted adenosine derivatives having the following formula [I] (hereinafter referred to often as the compound of the present invention): ##STR2## wherein R represents a hydrogen atom or a hydroxyl group, m is an integer of 2 to 7, n is 0 or an integer of 1 to 3, and R1, R2 and R3, which may be the same or different, each independently repre