An object of the present invention is to provide an oligonucleotide for rapidly and conveniently detecting bacteria of the genus Mycobacterium (acid-fast bacteria) or for identifying the bacterial species thereof, and a method and kit for detecting bacteria of the genus Mycobacterium (acid-fast bacteria) using such oligonucleotid. The present invention provides a method for identifying Mycobacterium tuberculosis, which comprises performing a nucleic acid amplification reaction using a primer for nucleic acid amplification that comprises a nucleotide sequence corresponding to a variable region in a 16S rRNA gene sequence of Mycobacterium tuberculosis and has at least 3 continuous nucleotides contained in the nucleotide sequence represented by SEQ ID NO: 1 at the 3′ end.