General formula (I) To decompose the acid peroxide ever high flow represented by the formula (In the formula, n represents an integer of 1 or 2, Ar represents an n-valent aromatic hydrocarbon group.) In the presence of an acid catalyst, the general formula (Ⅱ) Ar- (OH) n (Ⅱ) Characterized in that a process for producing a hydroxy aromatic compound represented by: (wherein, Ar and n are as defined above), as an acid catalyst, use of phosphoric acid as a silicate or hexafluoro borate, hexafluoro-tetrafluoro Hyde and a method of manufacture is disclosed hydroxy aromatic compound. According to such a method, well inhibit by-product of hydroxyacetone, it is possible to obtain a hydroxy aromatic compound in a high yield. In particular, it performs dividing the acid decomposition reaction in the first stage and the second stage performs the first stage of the reaction at a temperature of 50 ℃ to 95 ℃ from the first reactor, and lead to the resultant reaction mixture to a second reactor, where the reaction to the claim by performing a two-stage at a temperature 80 ℃ to 120 ℃, suppressing by-product of hydroxyacetone in particular effective, it is possible that even the hydroxy aromatic compounds for the purpose of obtaining a high yield.