There is provided a planarizing film-forming composition for a hard disk. A planarizing film-forming composition for a hard disk comprising a hydrophobic coating material having a photopolymerizable group and an aromatic group, containing a polymer or a combination of a polymer and a compound selected from the group consisting of a polymer (A1) including an aromatic group, having a molecular weight of 300 to 5000, and being a liquid at normal temperature under atmospheric pressure, a polymer (A2) including at least two photopolymerizable groups, having a molecular weight of 300 to 5000, and being a liquid at normal temperature under atmospheric pressure, a polymer (A3) including an aromatic group and at least two photopolymerizable groups, having a molecular weight of 300 to 5000, and being a liquid at normal temperature under atmospheric pressure, a compound (a1) including an aromatic group, having a molecular weight of 100 to 1000, and being a liquid at normal temperature under atmospheric pressure, a compound (a2) including at least two photopolymerizable groups, having a molecular weight of 100 to 1000, and being a liquid at normal temperature under atmospheric pressure, and a compound (a3) including an aromatic group and at least two photopolymerizable groups, having a molecular weight of 100 to 1000, and being a liquid at normal temperature under atmospheric pressure.