To provide alliinase derived from microorganisms simply and efficiently producing allicin from alliin on an industrial scale and putting the allicin to practical use as a pharmaceutical, and to provide a method for producing allicin using the alliinase.

The alliinase is a crude enzyme contained in a liquid obtained by fracturing a cell body after culturing Ensifer adhaerens AMA9794 strain (FERM P-19486) and has optical specificity selectively acting on (-)alliin. A method for producing the alliinase comprises culturing Ensifer adhaerens AMA9794 strain (FERM P-19486), producing alliinase in culture products and collecting the alliinase. The method for producing allicin comprises reacting the alliinase with an extract of a plant of the genus Allium or a solution containing alliin to produce the allicin.