This paper presents positron lifetime results which give information on the nature of vacancy defects induced by electron irradiation in bulk nitrogen doped (n(D)-n(A)= 2.3x10(17) cm(-3)) Cree 6H-SiC. The electron irradiations have been performed at different energies and with different fluences from 5x10(17) ecm(-2) to 3x10(18) ecm(-2). Positron lifetime have been measured with a 22 NaCl source as a function of temperature between 15 and 300 K. The lifetime spectra were analyzed as sums of two exponential lifetime components τ(i) weighted by the intensities I-i, convoluted with the resolution function. From the temperature dependence of the lifetime spectra we can infer that several vacancy defects exist in the electron irradiated n-type 6H-SiC. The nature of detected vacancy defects depends on the electron energy.