In this paper, we propose a Magnetic Energy Recovery Switch (MERS). The switch consists of four MOSFET elements and one capacitor. A power factor improvement is automatically possible regardless of the impedance and power frequency of the load by synchronized switching of MERS with a power supply. MERS itself generates voltage and compensates for the inductance voltage unlike a conventional series capacitor, so that another dc power supply is not needed. An experiment was carried out to demonstrate the automatic correction of the power factor. We can also expect energy saving of electromachies such as an electric motor by the power factor correction with MERS.