Vibronically excited but jet-cooled benzyl-type radicals were generated by the corona discharge of precursor 4-fluoro-o-xylene seeded in a large amount of inert carrier gas helium using a pinhole-type glass nozzle, from which the vibronic emission spectra were observed with a long-path monochromator in the visible region. From an analysis of the spectra observed, we identified the existence of two isomeric benzyl-type radicals, 2-methyl-4-fluorobenzyl and 2-methyl-5-fluorobenzyl radicals in corona discharge, and determined the electronic energy of the D-1 -> D-0 transition and several vibrational mode frequencies in the D-0 state of both isomers for the first time.