The mechanism that causes the end of lamp life (EOLL) phenomenon in a fluorescent lamp should be clarified to achieve an effective measure for that. The EOLL phenomenon, including the tungsten sputtering from an electrode, is investigated. We observed the electron emission from a lead in the vicinity of the stem glass. The electron emission causes the intermittent pulse discharge that heats up the stem glass. The concentration of lamp current directly into one of leads is another factor to heat up a small glass portion around the lead. The comparison of the stem glass resistance and the glow discharge impedance between leads after the filament disconnection indicates whether or not the stem glass will begin to soften. It was shown that the heating of a small glass portion around the lead was a dominant factor that resulted in the final stage of EOLL, that is, a substantial overheating of a lamp end portion. The way of operation for testing the life-ended fluorescent lamps is expected to contribute to the further understanding of the alkali metal adsorbate on metal surface.