The jet-cooled p-cyanobenzyl radical has been generated from p-tolunitrile and vibronically excited with a carrier gas, He, using a pinhole-type nozzle in a corona excited supersonic expansion. The vibronic emission spectrum of the p-cyanobenzyl radical in the transition of D-1(2(2)B(2)) --> D-0(1(2)B(2)) has been recorded with a long-path monochromator in the visible region. The spectrum was analyzed to obtain the vibrational mode frequencies of the p-cyanobenzyl radical in the ground electronic state with the aid of an ab initio calculation as well as those of p-tolunitrile.