PURPOSE: To prepare nitrobenzene, in high yield, by the vapor-phase nitration of benzene with a nitrating agent using a catalyst comprising an acidic compound oxide containing two or more metal oxides.

CONSTITUTION: The objective nitrobenzene is prepared by the vapor-phase nitration of benzene with a nitrating agent selected from NO2 and N2O4 using a catalyst comprising an acidic compound oxide (excluding silica.alumina) containing two or more metal oxides. An acidic compound oxide containing the oxide of Mo or W (e.g. MoO3-WO3), the oxide of Ti (e.g. TiO2-SnO2), the oxide of Si (e.g. WO3-SiO2), etc. can be used as the above catalyst. The reaction is carried out preferably at 80W250°C, using 0.1W3 moles of the nitrating agent per 1 mole of benzene in the presence of a diluent gas composed of an inert gas such as N2 gas.