A magnetic recording medium, a hard disk using the same, and a manufacturing method thereof are provided. In one example, the magnetic nano-particle medium is formed by depositing a magnetic nano-particle colloid on a substrate, wherein the axes of easy magnetization of respective crystalline particles are aligned with high accuracy. A layer of L10 alloy nano-particles which will exhibit magnetic properties through an order-disorder transition, and arranged at a substantially uniform spacing on a substrate, and a carbon-containing covering film for surrounding these nano-particles and making the spacing substantially uniform are provided. To the L10 alloy of the nano-particles, at least one non-magnetic element is added, or a covered layer comprising at least one non-magnetic layer is formed therearound. This makes it possible to implement a magnetic recording medium wherein the average diameter of nano-particles is small, and the nano-particle diameter dispersion is small, and the axes of magnetic anisotropy are aligned.