A seed-covering agent, which covers a seed surface and contains an iron powder and a binder, is specified such that, in the above-described iron powder, the mass ratio of an iron powder having a particle size of 63 μm or less to a total mass of the iron powder is 0% or more and 75% or less, the mass ratio of an iron powder having a particle size of more than 63 μm and 150 μm or less to the total mass of the iron powder is 25% or more and 100% or less, and the mass ratio of an iron powder having a particle size of more than 150 μm to a total mass of the iron powder is 0% or more and 50% or less, and the average particle size of the above-described binder is 1 to 150 μm.