PROBLEM TO BE SOLVED: To provide a biofilm inhibitor excellent in the inhibitory power against forming biofilm derived from candida, despite having no germicide as an essential ingredient.SOLUTION: A biofilm inhibitor comprises, as an active ingredient, a glycerol monofatty acid ester and/or glyceryl monoundecenoate having 7-14C saturated fatty acid residue as a glycerol fatty acid ester; a diglyceryl monolaurate as a diglycerol fatty acid ester; at least one compound in the group consisting of, as a sucrose fatty acid ester, 10-18C saturated fatty acid residue-bearing sucrose monofatty acid ester, sucrose dicaprate and sucrose dilaurate; and a sorbitan monolaurate as a sorbitan fatty acid ester.