A low-cost electrochemical capacitor is provided which has high capacity and excellent charging and discharging characteristics, simultaneously has excellent safety and reliability, and has the basic performance as a capacitor, achieved in that, as the electrolyte between a negative electrode and a positive electrode, a solution of an ambient temperature molten salt and a specific polyether copolymer is allowed to gel using a specific photoreaction initiator and is held between the two electrodes. This low-cost electrochemical capacitor has the basic performance of a capacitor, has high capacity and excellent charging and discharging characteristics without use of a separator, and simultaneously has excellent safety and reliability.