Embodiments of the invention provide a coil unit for a thin film inductor, a manufacturing method of a coil unit for a thin film inductor, a thin film inductor, and a manufacturing method of a thin film inductor. According to an embodiment, there is provided a coil unit for a thin film inductor. The coil unit includes an insulator having a dual insulating layer of different materials, and coil patterns respectively embedded in upper and lower surfaces of the insulator. The coil patterns include a coil pattern formed of a plurality of plating layers.