The electrochemical behavior of m-nitrosulphonic acid of benzene was studied by polarography, voltammetry at glassy carbon electrode, electrolysis at the controlled potential, and electrolysis in galvanostatic mode. A distinguishing feature of the m-nitrosulphonic acid of benzene electroreduction, as compared with that of aromatic nitro-compounds, both on mercury dropping electrode and glassy carbon electrode, is shown to be a strong dependence of parameters and shape of the polarization curve on the supporting electrolyte solution composition and рН in neutral and alkaline solutions. The two waves observed are bound to the reduction of undissociated m-nitrosulphonic acid of benzene molecule and its anion; the reduction intermediately product is hydroxylaminesulphonic acid of benzene. The wave of its further reduction to m-aminosulfonic acid of benzene is camouflaged by the supporting-electrolyte discharge. Ammoniac-buffered solutions can be recommended for preparative electrosynthesis of m-aminosulfonic acid of benzene because its yield in the electrolysis at nickel cathode in galvanostatic mode in these solutions is as high as 92.8%, with current efficiency of 82.0%.