PROBLEM TO BE SOLVED: To provide a rice seed coating agent that is reduced in peeling of iron powder, and can omit a finishing step in the coating.SOLUTION: A rice seed coating agent contains iron powder and a binding agent and additives. The iron powder is configured such that a mass ratio of the iron powder with a particle size of 45 μm or less is more than 35% and less than 85%, and the mass ratio of the iron powder with the particle size of 63 μm or less is more than 75%. In the additives, the specific surface area is 10-300 m/g, and the average particle size is 500 nm or less. Preferably, the total of the binding agent and the additive amount of the additives is 5-30 pts.mass to the iron powder of 100 pts.mass, and 50-90 mass % to the total of the binding agent and the additives is the additives. Preferably, the additives contain one or more kinds among SiO, AlO, CaCO, MgCOand magnesium aluminometasilicate. Preferably, the binding agent is a trivalent iron compound of hematite, goethite, etc.SELECTED DRAWING: Figure 5