A high efficiency rectifier which can be replaced easily by a two-terminal diode and can reduce loss during conduction. Between the source-drain of an MOSFET (2) incorporating a parasitic diode (2a), a micropower converter section (3) for boosting the conduction voltage Vds between the source-drain up to a predetermined level, a self-drive control section (4) operating with the output voltage fromthe micropower converter section (3) are connected. When a current is permitted to flow between the source and the drain, the micropower converter section (3) generates the power supply voltage of the self-drive control section (4) from the conduction voltage Vds, and the self-drive control section (4) sustains drive control of the MOSFET (2).