A base for a magnetic recording medium, includes a substrate made of an Al alloy and having a surface, and a film made of a NiP-based alloy and plated on the surface of the substrate. The film has a thickness of 7 μm or greater, and a ratio E/ρ is 29 or greater, where E [GPa] denotes the Young's modulus of the substrate, and ρ [g/cm3] denotes a density of the substrate.