NEGATIVE ELECTRODE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, METHOD FOR MANUFACTURING THE SAME, NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a negative electrode material for a lithium ion secondary battery realizing a lithium ion secondary battery having excellent cycle characteristics and inhibited from expanding with charges.SOLUTION: The negative electrode material for a lithium ion secondary battery contains composite particles made by compositing first particles containing a carbonaceous material A and second particles containing silicon using a carbonaceous material B. When the composite particle is observed in cross section, the ratio of the content of silicon atoms in the inner region from the circumference to a depth of one-eighth of the length of a minor axis intersecting a major axis of the maximum length at right angles at the midpoint of the major axis to the content of silicon atoms in the inner region of a circle having a radius of one-eighth of the length of the minor axis and centered at the midpoint of the major axis, is 2 or greater.