In this article ac-conductivity was analyzed of NaCl single crystals doped with bivalent additive Co2+ in low concentrations (500 ppm). Analysis of the ac-conductivity data took into account contributions of Cole-Cole dielectric relaxation of dipoles (vacancy-impurity cation pair associates), Almond-West relaxation of charge carriers (cation vacancies) and electrode effects in the form of modified Warburg impedance. Results of the analysis show that the high-frequency conductivity of doped NaCl is completely due to the dipole relaxation. The dipoles concentration was estimated as 25-50 ppm slightly increasing with temperature in the temperature range 120-220 degreesC in accord with the expected one from the classical Schottky-Wagner approach. No sign of Jonscher's 'Universal Dielectric Response' was detected in the samples studied. Within experimental error the dipole relaxation peaks are of ideal Debye form.