To provide a lithium secondary battery with a high capacity and superior in a high rate discharge characteristic and a charge and discharge cycle characteristic.

In the lithium secondary battery having at least a negative electrode (201), a positive electrode (203), and an ion conductor (202), the positive electrode (203) is constituted of lithium metal composite oxide particles, and the lithium metal composite oxide particles contain a plurality of secondary particles of a slender shape assembled and formed so that a plurality of primary particles in which the average particle diameter is 0.1-1 μm form voids between particles, and the secondary particles have a rod shape or a plate shape in which the average length in the longitudinal direction is 5-15 μm.