The invention provides a 5'-amino-2'-fluoro-2',5'-dideoxynucleoside compound represented by the formula [1]: ##STR00001## wherein R.sub.1 represents a nucleic acid base which may have a protecting group; R.sub.2 represents a hydrogen atom or an amino protecting group; and R.sub.3 represents a hydrogen atom or a hydroxyl protecting group. The invention also provides a dideoxynucleoside-insoluble carrier bound substance and an oligonucleotide analogue involving the dideoxynucleoside compound.