A lithium ion secondary battery comprising a structure in which at least one positive electrode and at least one negative electrode are alternately adjacent to each other via a separator (4, 5), the at least one positive electrode comprising: a positive electrode current collector composed of a metal porous body having a three-dimensional network structure; a first positive electrode active material including a high-capacity active material held on one side of the positive electrode current collector; and a second positive electrode active material including a high-power active material held on the other side of the positive electrode current collector, and the at least one negative electrode comprising: a negative electrode current collector composed of a metal porous body having a three-dimensional network structure; a first negative electrode active material including a high-capacity active material held on one side of the negative electrode current collector; and a second negative electrode active material including a high-power active material held on the other side of the negative electrode current collector, wherein the first positive electrode active material faces the first negative electrode active material adjacent thereto via a first separator, and the second positive electrode active material faces the second negative electrode active material of the negative electrode adjacent thereto via a second separator, wherein the first positive electrode active material comprises at least one selected from a group consisting of Li(Ni 5/10 Co 2/10 Mn 3/10)O 2, Li(Ni 6/10 Co 2/10 Mn 2/10)O 2, Li(Ni 8/10 Co 1/10 Mn 1/10)O 2, and Li(Ni 0.8 Co 0.15 Al 0.05)O 2, the second positive electrode active material comprises at least one selected from a group consisting of Li(Ni 1/6 Co 4/6 Mn 1/6)O 2 and Li(Ni 1/3 Co 1/3 Mn 1/3)O 2; the first negative electrode active material comprises at least one selected from a group consisting of artificial graphite, natural graphite, Si, and SiO, the second negative electrode active material comprises hard carbon; and in the three-dimensional network structure of the positive and negative electrode current collectors columnar skeletons are three-dimensionally connected. a structure in which at least one positive electrode and at least one negative electrode are alternately adjacent to each other via a separator (4, 5), the at least one positive electrode comprising: a positive electrode current collector composed of a metal porous body having a three-dimensional network structure; a first positive electrode active material including a high-capacity active material held on one side of the positive electrode current collector; and a second positive electrode active material including a high-power active material held on the other side of the positive electrode current collector, and a positive electrode current collector composed of a metal porous body having a three-dimensional network structure; a first positive electrode active material including a high-capacity active material held on one side of the positive electrode current collector; and a second positive electrode active material including a high-power active material held on the other side of the positive electrode current collector, and the at least one negative electrode comprising: a negative electrode current collector composed of a metal porous body having a three-dimensional network structure; a first negative electrode active material including a high-capacity active material held on one side of the negative electrode current collector; and a second negative electrode active material including a high-power active material held on the other side of the negative electrode current collector, a negative electrode current collector composed of a metal porous body having a three-dimensional network structure; a first negative electrode active material including a high-capacity active material held on one side of the negative electrode current collector; and a second negative electrode active material including a high-power active material held on the other side of the negative electrode current collector, wherein the first positive electrode active material faces the first negative electrode active material adjacent thereto via a first separator, and the second positive electrode active material faces the second negative electrode active material of the negative electrode adjacent thereto via a second separator, wherein the first positive electrode active material comprises at least one selected from a group consisting of Li(Ni 5/10 Co 2/10 Mn 3/10)O 2, Li(Ni 6/10 Co 2/10 Mn 2/10)O 2, Li(Ni 8/10 Co 1/10 Mn 1/10)O 2, and Li(Ni 0.8 Co 0.15 Al 0.05)O 2, the second positive electrode active material comprises at least one selected from a group consisting of Li(Ni 1/6 Co 4/6 Mn 1/6)O 2 and Li(Ni 1/3 Co 1/3 Mn 1/3)O 2; the first negative electrode active material comprises at least one selected from a group consisting of artificial graphite, natural graphite, Si, and SiO, the second negative electrode active material comprises hard carbon; and in the three-dimensional network structure of the positive and negative electrode current collectors columnar skeletons are three-dimensionally connected.