PURPOSE: To efficiently produce the subject compound by hydroxylating phenols and/or alkoxybenzenes with H2O2 using a crystalline substance containing silicon oxide and titanium oxide having a specific crystallite size as a catalyst.

CONSTITUTION: Phenols and/or alkoxybenzenes are hydroxylated by using a crystalline substance, containing silicon oxide and titanium oxide and having a crystallite size within the range of <10,000 as a catalyst to afford aromatic hydroxyl compounds, i.e. aromatic dihydroxy compounds or alkoxyphenols. The hydroxylation can be efficiently carried out and advanced at a high reaction rate by the aforementioned method to industrially and advantageously produce the subject compound. The resultant compound is useful as various organic synthetic intermediates or raw material substances and further in the field of reducing agents, rubber chemicals, dyes, medicines, perfumes, polymerization inhibitors, oxidation inhibitors, etc.