An electromagnetic contactor comprising: a pair of fixed contacts (111, 112) disposed and fixed maintaining a predetermined interval and a movable contact disposed so as to be connectable to and detachable from the pair of fixed contacts (111, 112); an electromagnet unit that drives the movable contact; and a drive circuit that drives the electromagnet unit, the electromagnet unit including at least: a movable plunger biased by a return spring; a coil that enables the movable plunger to move; characterized in that the electromagnet unit further includes a ring-form permanent magnet, magnetized in the direction in which the movable plunger is movable, disposed and fixed so as to enclose a peripheral flange portion formed on the movable plunger; a magnetic yoke of a flattened U-shape; a cylindrical auxiliary yoke fixed in a central portion of a bottom plate portion of the magnetic yoke; and an upper magnetic yoke fixed between upper ends forming an opened end of the magnetic yoke, wherein the permanent magnet is fixed to the upper surface of the upper magnetic yoke, the drive circuit including: a power source that supplies power to the coil; a pulse drive circuit that outputs and supplies to the coil an engage pulse that causes an operation suctioning the movable plunger and a hold pulse that, when the movable plunger is subjected to a suctioning operation by the engage pulse, maintains the suctioning operation; and a flywheel circuit having a semiconductor switching element connected in parallel to the coil. a pair of fixed contacts (111, 112) disposed and fixed maintaining a predetermined interval and a movable contact disposed so as to be connectable to and detachable from the pair of fixed contacts (111, 112); an electromagnet unit that drives the movable contact; and a drive circuit that drives the electromagnet unit, the electromagnet unit including at least: a movable plunger biased by a return spring; a coil that enables the movable plunger to move; characterized in that the electromagnet unit further includes a ring-form permanent magnet, magnetized in the direction in which the movable plunger is movable, disposed and fixed so as to enclose a peripheral flange portion formed on the movable plunger; a magnetic yoke of a flattened U-shape; a cylindrical auxiliary yoke fixed in a central portion of a bottom plate portion of the magnetic yoke; and an upper magnetic yoke fixed between upper ends forming an opened end of the magnetic yoke, wherein the permanent magnet is fixed to the upper surface of the upper magnetic yoke, a movable plunger biased by a return spring; a coil that enables the movable plunger to move; a ring-form permanent magnet, magnetized in the direction in which the movable plunger is movable, disposed and fixed so as to enclose a peripheral flange portion formed on the movable plunger; a magnetic yoke of a flattened U-shape; a cylindrical auxiliary yoke fixed in a central portion of a bottom plate portion of the magnetic yoke; and an upper magnetic yoke fixed between upper ends forming an opened end of the magnetic yoke, wherein the permanent magnet is fixed to the upper surface of the upper magnetic yoke, the drive circuit including: a power source that supplies power to the coil; a pulse drive circuit that outputs and supplies to the coil an engage pulse that causes an operation suctioning the movable plunger and a hold pulse that, when the movable plunger is subjected to a suctioning operation by the engage pulse, maintains the suctioning operation; and a flywheel circuit having a semiconductor switching element connected in parallel to the coil. a power source that supplies power to the coil; a pulse drive circuit that outputs and supplies to the coil an engage pulse that causes an operation suctioning the movable plunger and a hold pulse that, when the movable plunger is subjected to a suctioning operation by the engage pulse, maintains the suctioning operation; and a flywheel circuit having a semiconductor switching element connected in parallel to the coil.