An insulating device includes a first element, a second element, a first lead, a second lead, and a resin member. The second element is electrically connected to the first element. The first element is mounted on the first lead. The second lead includes a first surface and a second surface, the second surface being at a side opposite to the first surface. The second element is mounted to the first surface. the second lead is arranged to overlap the first element in a direction crossing the second surface of the second lead. The resin member seals the first element, the second element, the first lead, and the second lead.