PURPOSE: To obtain the subject compound in high purity and yield, useful as e.g. a food preservative, plasticizer, by culturing microbes belonging to Rhodococcus and having ability to produce 3-hydroxybenzoic acid in a medium containing isophthalic acid as the main carbon source.

CONSTITUTION: Microbes belonging to Rhodococcus and having ability to produce 3-hydroxybenzoic acid, e.g. Rhodococcus L-1 strain (FERM P-10614) are cultured in a medium containing isophthalic acid as the main carbon source. The objective 3-hydroxybenzoic acid is obtained in a state of low levels of byproducts from the cultured product, thus being easy to separate and purify the same.