Provided is a highly efficient rectifier which can readily replace a two-terminal diode and whose conduction loss is reduced from that of the two-terminal diode. Connected between the source and drain of a MOSFET (2) including a parasitic diode (2a) are: a micro-power converter section (3) for boosting a conduction voltage Vds between the source and drain to a predetermined voltage; and a self-drive control section (4) that operates based on a voltage outputted from the micro-power converter section (3). When the source and drain are conductive with each other, the micro-power converter section (3) generates, from the conduction voltage Vds, a power source voltage for the self-drive control section (4), and the self-drive control section (4) continues drive control of the MOSFET (2).