A first connector of a connector set includes first internal terminals, a first insulation member that fixes the first internal terminals, and first external terminals having a surrounding shape portion that surrounds the first internal terminals and the first insulation member. The second connector includes second internal terminals, a second insulation member that fixes the second internal terminals, and a second external terminal having a surrounding shape portion that surrounds the second internal terminals and the second insulation member. The first external terminals have cutout portions at a portion that is part of the surrounding shape portion of the first external terminal and faces a ground conductor formed at a mounting position of the second connector of the second circuit substrate.