Provided is a positive electrode material that allows reducing the low-temperature resistance of a secondary battery. The positive electrode material of a secondary battery includes positive electrode active material particles each having a void in the interior, and a compound (A) that is present at least within the void. The average diameter of the void is not less than 0.01 μm and not more than 1 μm. The compound (A) is a nitrile group-containing polymer, and the proportion of nitrogen atoms, relative to metal atoms included in the positive electrode active material particles, other than lithium, is not less than 1 atom % and not more than 10 atom %; alternatively, the compound (A) is an alkoxysilane compound, and then the proportion of silicon atoms, relative to metal atoms included in the positive electrode active material particles, other than lithium, is not less than 1 atom % and not more than 10 atom %.