Abstract: Disclosed is an electromagnetic switch device for star-delta connections including a body, three power terminals respectively connected to three-phase power lines at one side of the body, three main starting terminals respectively connected to one-side terminals of a three-phase electric motor at the other side of the body, three star-delta terminals respectively connected to the other-side ends of the three-phase electric motor at the other side of the body, an electromagnet for a main circuit and an electromagnet for star-delta connections disposed at a lower portion of the body in such a fashion that they are laterally aligned with each other, each of the electromagnets including a fixed core and a coil wound around the fixed core, a main circuit switching unit serving to selectively connect each of the main starting terminals to an associated one of the power terminals in accordance with a magnetization of the main circuit-end electromagnet, and a star-delta connection switching unit serving to selectivel