Electrochemical cell

An electric double layer capacitor with a low resistance value is disclosed. The electric double layer capacitor includes an electrochemical device in the inside of a housing container and capable of achieving charge and discharge via external terminals, wherein the electrochemical device includes a pair of electrodes, a separator disposed between the pair of electrodes, and an electrolytic solution with which the pair of electrodes and the separator are impregnated; when a volume between the pair of electrodes is designated as Ve, and a volume of a void in an inter-electrode part of the separator disposed between the pair of electrodes is designated as Se, an inter-electrode part void ratio Re is defined as Re = Se/Ve x 100 (%); and when a thickness of the inter-electrode part is designated as L2 (µm), and a separator evaluation index le is defined as le = L2/Re (µm/%), a relation of le ¤ 1.0 (µm/%) is satisfied.