Cathode material for lithium ion secondary battery, cathode for lithium ion secondary battery, lithium ion secondary battery, and method for producing each of same

Provided is a cathode material that is for a lithium ion secondary battery and that has superior energy density and electron conductivity. The cathode material for a lithium ion secondary battery comprises a composite particle (20) of: a first particle (30), which is a cathode active material represented by general formula Li x Mn a M1 b O 2 (where in the formula, M1 is at least one element selected from the group consisting of Ni, Cu, Zn, Co, Fe, Cr, V, Ti, Mg, Al, Sn, Mo, Nb, V, Zr, Ta, Ru, and W, 1.0 < x ≤ 1.4, 0 < a < 1.0, 0 < b < 1.0, and a+b ≤ 1.0); and a second particle (40, 50) having an electrical conductivity of at least 1.0×10 -5 S/m.