To provide a composite magnetic body that is placed in a narrow case, adopted even for a part receiving a heavy load, and is applicable to an electromagnetic interference suppression body with flame resistance, to provide its manufacture and the electromagnetic interference suppression body using the composite magnetic body.

An organic flame resistance agent and an inorganic flame resistance agent are contained in the composite magnetic body including Fe-based flat soft magnetism powder and a coupling agent to provide flame resistance. To manufacture the composite magnetic body, the organic flame resistance agent is added to the Fe-based flat soft magnetic powder and mixed and kneaded with the coupling agent. Furthermore, the electromagnetic interference suppression body is manufactured by using the composite magnetic body.