An electrical device includes a container, a conversion unit, an outer cover and an inner cover. The container is provided with an inner bottom surface and an inner which define an accommodating channel together. An inlet of the accommodating channel is opposite to the inner bottom surface. The conversion unit is disposed within the accommodating channel. The outer cover covers the inlet of the accommodating channel. The inner cover is disposed within the accommodating channel, and located between the conversion unit and the outer cover. One part of the conversion unit extends to the opening, and at least one outer edge of the inner cover is connected to an inner wall of the container.