A catalyst for the aromatization of lower hydrocarbons which is improved in the activity life stability in terms of methane conversion, benzene formation rate, naphthalene formation rate and BTX formation rate (total formation rate of benzene, toluene, and xylene) and brings about an increase in the yield of useful aromatic compounds such as benzene and toluene, comprising a metallosilicate and molybdenum and silver which are supported on the metallosilicate. It is preferable that the catalyst be prepared by modifying a zeolite consisting of a metallosilicate with a silane compound which has a molecular diameter larger than the pore diameter of the zeolite and bears both an amino group selectively reactive with a Br?nsted acid site of the zeolite and a linear hydrocarbon group and then making molybdenum and silver supported on the modified zeolite. In producing aromatic compounds, the catalyst enables the reaction of a reaction gas containing both lower hydrocarbons and carbon dioxide.