An RF device which has excellent durability and communication capability, and which can be manufactured at a low cost, and a method of manufacturing such an RF device are disclosed. The RF device has an insulating substrate for blocking radio waves and preventing noise from being produced. The RF device also has a signal processing circuit formed on the insulating substrate so that it does not need junctions which would be formed by a mounting process. An antenna is integrally formed with the signal processing circuit on the insulating substrate, and is connected to the signal processing circuit.