Electron-Impact Ionization of MgA pulsed crossed beam technique is used to measure inonization cross-sections of metallic atoms. Relative values of cross-sections of single, double and triple inonization of magnesium have been successfully measured with good accuracy over the o-700 eV range. Absolute values of cross sections have been obtained by normalization to a theoretical value at high electron energy. Results are compared to previously published values and, for single inonization in particular, a comparison with theoretical cross-extions is perfomed.