An anode active material (1) of the present invention for use in a nonaqueous secondary battery, the anode active material includes: a main crystalline phase (2) including a lithium-containing transition metal oxide containing manganese and having a spinel structure; and a sub crystalline phase (3) contained in the main crystalline phase, the sub crystalline phase (3) being identical in oxygen arrangement to the lithium-containing transition metal oxide and different in elementary composition from the lithium-containing transition metal oxide, a main crystalline phase part (2') around the sub crystalline phase (3) and the sub crystalline phase (3) having a same crystal orientation.