Excitation of argon metastable levels (43P2 +43Po) in a nonselfsustained discharge in Ar(>99%)+N2(<__l%) gas mixtures has been investigated by measuring N 2 second positive group which is the result of excitation transfer from Ar metastables to N 2 molecules. The method is based on the assumption, experimentally verified, that addition of small quantities of N 2 do not change markedly the probability of Ar excitation. The obtained excitation coefficients for production of Ar m in the E/N range (20-70) x 10 21 Vm 2 are (3.5-13) x 10 22 m 2 with an estimated uncertainty of -t-50 %. Simultaneously, excitation coefficients for direct excitation of nitrogen C-state by swarm electrons in Ar-N 2 mixtures have been obtained. A comparison of nitrogen spectra excited by electrons and by argon metastables showed significant differences in relative population of vibrational and rotational levels of the N2(CaH,) state in these two cases.