To obtain an antimicrobial agent for foods, exhibiting bacteriostatic effect on microorganisms in wide range, excellent in safety and having no influence on taste and texture of food by using a polyglycerol fatty acid ester having a specific monoester content.

This antimicrobial agent for foods is obtained by compounding a polyglycerol fatty acid ester in which a fatty acid constituting the polyglycerol fatty acid ester is one kind of fatty acid or a mixture of two or more kinds of fatty acids among caprylic acid, caprylic acid, lauric acid and myristic acid, and a polyglycerol part constituting the polyglycerol fatty acid ester is di-, tri-, tetra or pentaglycerol and a monoester content constituting the polyglycerol fatty acid is ≥50wt.% as an active ingredient. The antimicrobial agent exhibits bacteriostatic effect on microorganisms and is excellent in safety and has no adverse effect on taste texture and physical properties of foods.