A switch device includes a plurality of lead frames that is conductive and configured to electrically connectable to an external device, a contact-separation mechanism configured to allow the plurality of lead frames to be electrically connected to and separated from each other, and an electric element configured to connect the plurality of lead frames to each other. The electric element is surface-mounted on the lead frames and sealed with resin. In each of the lead frame, the boundary, such as a groove or a notch, is formed along the outer edge of the arrangement position of the electric element.