Abstract: Dihydric phenols are produced preferentially in high yields by having monohydric phenols or phenyl ethers oxidized by an organic peracid using, as a catalyst, at least one member selected from the group consisting of peracid stabilizers, polycarboxylic acids containing N or OH and possessed of a structure from which heavy metal ion-chelating property can theoretically be assumed, magnesium salts, sodium salts and potassium salts thereof, sodium salt, potassium salt and lower alkyl esters of phosphoric acid, and sodium salt and lower alkyl esters of pyrophosphoric acid.