Novel means that enables detection of the monocytogenes bacterium alone distinctly from other bacteria belonging to the genus Listeria with sufficiently high accuracy is disclosed. The present inventors intensively analyzed the genome of the monocytogenes bacterium to identify two genes (the lmo0084 gene and the lmo2736 gene) as target regions with which the monocytogenes bacterium can be specifically detected distinctly from other bacteria belonging to the genus Listeria utilizing a nucleic acid amplification method. By a further intensive study of the base sequences of these two genes, primer setting regions for highly accurate, specific detection of the monocytogenes bacterium alone were identified, and preferred particular examples of PCR primer sets, LAMP primer sets, and real-time PCR primer-probe sets were established.