Provided are an electrode active material having a plurality of pores and a secondary battery including the same, and more particularly, a porous electrode active material including silicon-based oxide expressed by SiOx (0.5≦x≦1.2) and having a Brunauer, Emmett, and Teller (BET) specific surface area ranging from 2 m2/g to 100 m2/g, and a secondary battery including a cathode including a cathode active material, a separator, an anode including an anode active material, and an electrolyte, in which the anode active material includes a porous electrode active material including silicon-based oxide expressed by SiOx (0.5≦x≦1.2) and having a BET specific surface area ranging from 2 m2/g to 100 m2/g.