Disclosed is a polarizable electrode material for an electric double layer capacitor with a high energy density and excellent long-term reliability, as well as an electric double layer capacitor in which the polarizable electrode material is used. The polarizable electrode material includes porous carbon particles, a conductive assistant, a tungsten oxide powder and a binder, wherein the tungsten oxide is dispersed in the polarizable electrode material so that the tungsten oxide per 1 g of the polarizable electrode material has a surface area of 0.2 m2 or more and less than 6 m2.