Provided is a microorganism that is able to efficiently produce protocatechuic acid or a salt thereof by using a saccharide as a raw material, and a method of efficiently producing protocatechuic acid or a salt thereof by using the microorganism. Provided is a transformant having protocatechuic acid producing ability, subjected to modifications of enhancement of 3-dehydroshikimate dehydratase activity; enhancement of chorismate pyruvate lyase activity; and enhancement of 4-hydroxybenzoate hydroxylase activity. Also provided is a method of producing protocatechuic acid or a salt thereof, including the step of culturing the transformant in a reaction solution containing a saccharide so as to cause the transformant to produce protocatechuic acid or a salt thereof.