Magnetic graphene can be prepared from a graphite intercalation compound (GIC) with accepter-type intercalator, FeCl3. When the FeCl3-GIC is treated with primary amines at 90 °C for 6 h, the GIC is expanded to a few layers. The expansion is further facilitated, as the alkyl chain of primary amines becomes long, while tertiary amines cannot penetrate inside the GIC because of their steric hindrance. Then the expanded-GIC is sonicated in pyridine to exfoliate the graphene sheets. The obtained product indicated a typical superparamagnetic behavior and had an excellent durability in acid conditions. This approach using FeCl3-GIC, primary amine and pyridine is preferable for the mass production of magnetic graphene because of the mild reaction condition and the short treatment time for exfoliation from the chemically stable FeCl3-GIC.