A positive electrode for a lithium ion capacitor includes a positive electrode layer which, after a pretreatment for measurement, has a volume of pores having pore size of not lower than 1.0 nm and lower than 1.4 nm of not lower than 0.11 cc/g, calculated by an HK method, and total pore volume calculated by a BET method of not more than 1.1 cc/g. In the pretreatment: the positive electrode is taken out of a cell of cell voltage of 3 V, cut out and immersed in 10 cc of dehydrated acetonitrile per 1 cm3 of the positive electrode at 25° C. for 10 minutes with stirring. This immersion is repeated three times, and the positive electrode is in a pre-drying at 60° C. for 1 hour. The positive electrode layer is then scraped off from the positive electrode and dried for 2 hours at 200° C. and pressure reduced to 5.5 Pa.