An electrode material for a lithium-ion secondary battery of the present invention is secondary particles including inorganic particles represented by General Formula LiFexMn1-x-yMyPO4 and a carbonaceous film coating surfaces of the inorganic particles, in which an amount of carbon is 0.5% by mass to 2.5% by mass, a specific surface area is 10 m2/g to 20 m2/g, a first particle diameter (D90(a)) at which a cumulative volume percentage of a particle size distribution of secondary particles is 90% before an ultrasonic treatment is 20 mm to 40 mm, a second particle diameter (D90(b)) at which the cumulative volume percentage of the particle size distribution of the secondary particles is 90% after the ultrasonic treatment is 10 mm to 15 mm, and a ratio (D90(b)/D90(a)) of the second particle diameter (D90(b)) to the first particle diameter (D90(a)) is 0.3 to 0.5.