An electrical double layer capacitor has an electrolyte included of a non-aqueous solvent and a supporting salt dissolved in the non-aqueous solvent. A pair of polarizing electrodes are disposed in confronting relation with one another. A separator is disposed between the polarizing electrodes. The supporting salt contained in the electrolyte exists only in regions proximate a surface of the polarizing electrodes when the electrical double layer capacitor is fully charged. When the electrical double layer capacitor is charged at 3.3 V for 24 hours, a charged current after 24 hours is in the range of from about 5 .mu.A/cm.sup.2 to about 22 .mu.A/cm.sup.2 per unit area of the polarizing electrodes.