One aspect of the present invention is an antimicrobial agent including at least one of Bacillus subtilis and a culture of Bacillus subtilis, the Bacillus subtilis showing a peak at at least one mass-to-charge ratio (m/z) selected from the group consisting of a range of 3045.5±0.58 (m/z), a range of 6942.5±0.58 (m/z), and a range of 9140.5±0.58 (m/z) in mass analysis by means of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).
