A phase control switchgear applied to a configuration in which a three-phase switchgear is connected between a power source (10a, 10b, 10c) and a neutral-ungrounded or neutral-noneffectively-grounded no-load three-phase transformer to control a closing phase of the phase control switchgear, the phase control switchgear comprising: a power-source-side voltage detection unit that is configured to detect a power-source-side voltage in each phase on the power source side; a load-side voltage detection unit that is configured to detect a load-side voltage in each phase on the three-phase transformer side; a power-source-side magnetic-flux calculation unit that is configured to integrate the power-source-side voltage in each phase to calculate the power-source-side magnetic flux in each phase; a load-side magnetic-flux calculation unit that is configured to integrate the load-side voltage in each phase to calculate the load-side magnetic flux in each phase; a phase detection unit that is configured to determine a switch-on order based on an absolute value of the load-side magnetic flux in each phase after opening of the three-phase switchgear; and a switch-on-command control unit that is configured to control the three-phase switchgear so that each phase is individually switched on in the target switch-on-phase of each phase, wherein the phase detection unit is configured to detect, after opening of the three-phase switchgear, a phase having a largest absolute value of a load-side magnetic flux in each phase and to designate the detected phase as a first switch-on-phase, configured to designate arbitrary phases other than the first switch-on-phase are respectively designated as a second switch-on-phase and a third switch-on-phase, and configured to designate a phase in which a magnetic flux error between the load-side magnetic flux and a power-source-side magnetic flux due to mechanical operating variations of the three-phase switchgear is smaller, among two magnetic-flux matching phases in which a polarity and a size of the load-side magnetic flux in each phase match with those of the power-source-side magnetic flux in each phase on the power source side in one cycle, as a target switch-on-phase of each phase, for each of the phases, and wherein the switch-on-command control unit is configured to switch on each phase individually in the target switch-on-phase of each phase. a power-source-side voltage detection unit that is configured to detect a power-source-side voltage in each phase on the power source side; a load-side voltage detection unit that is configured to detect a load-side voltage in each phase on the three-phase transformer side; a power-source-side magnetic-flux calculation unit that is configured to integrate the power-source-side voltage in each phase to calculate the power-source-side magnetic flux in each phase; a load-side magnetic-flux calculation unit that is configured to integrate the load-side voltage in each phase to calculate the load-side magnetic flux in each phase; a phase detection unit that is configured to determine a switch-on order based on an absolute value of the load-side magnetic flux in each phase after opening of the three-phase switchgear; and a switch-on-command control unit that is configured to control the three-phase switchgear so that each phase is individually switched on in the target switch-on-phase of each phase, wherein the phase detection unit is configured to detect, after opening of the three-phase switchgear, a phase having a largest absolute value of a load-side magnetic flux in each phase and to designate the detected phase as a first switch-on-phase, configured to designate arbitrary phases other than the first switch-on-phase are respectively designated as a second switch-on-phase and a third switch-on-phase, and configured to designate a phase in which a magnetic flux error between the load-side magnetic flux and a power-source-side magnetic flux due to mechanical operating variations of the three-phase switchgear is smaller, among two magnetic-flux matching phases in which a polarity and a size of the load-side magnetic flux in each phase match with those of the power-source-side magnetic flux in each phase on the power source side in one cycle, as a target switch-on-phase of each phase, for each of the phases, and wherein the switch-on-command control unit is configured to switch on each phase individually in the target switch-on-phase of each phase.