To provide mass production of lithium-transition metal composite oxide for a lithium secondary battery electrode material of certain high quality by baking an object to be baked containing a lithium compound and a transition metal compound.

The lithium-transition metal composite oxide for the lithium secondary battery electrode material is manufactured by housing the object to be baked containing the lithium compound and the transition metal compound in the baking container having a vent hole in a part other than a top face, and baking it. Since the vent hole is in a part other than the top face, intrusion of impurities such as foreign matter, bulky particles, or the like during baking is prevented. Since atmospheric gas can be smoothly communicated from a vent part, the lithium-transition metal composite oxide satisfying required performance in a high level for lithium secondary battery application can be industrially massively produced at constant high quality.