In a magnetic disk including a magnetic layer, a protecting layer and a lubricating layer on a substrate, the lubricating layer is formed by a self assembly monolayer. A material of the self assembly monolayer is a hydrocarbon-based silane agent or a partial fluorinated hydrocarbon-based silane agent. The magnetic layer and the protecting layer (P) are sequentially formed on the substrate, and then the substrate on which the magnetic layer and the protecting layer (P) are formed is immersed in a solution containing the hydrocarbon-based silane agent or the partial fluorinated hydrocarbon-based silane agent, and thus a lubricating layer (L) is formed on the protecting layer (P).