PROBLEM TO BE SOLVED: To provide a hair growth promoter having a higher penetration effect into a deep part of a scalp and a higher sustained release effect into the deep part of the scalp of an effective component having a hair-growing effect.SOLUTION: The hair growth promoter contains a particulate matter formed by coating a first layer on at least the surface of ultrafine particle, wherein the ultrafine particle is a magnetic ultrafine particle having an average particle size in the nanometer order, and the first layer is an effective component for growing hair, and the average particle size of the particulate matter is in the ten-nanometer order.
