A static switch for switching between electrical connection and disconnection between an alternating-current power supply and a load , the static switch comprising: a thyristor switch connected between the alternating-current power supply and the load and including a pair of arms connected in anti-parallel, each of the arms including a plurality of thyristors connected in series; and a controller configured to perform on-off control of the thyristor switch , the thyristor switch being configured to be turned on in response to a gate signal supplied from the controller , and turned off in response to a current coming to zero in a state in which the gate signal is interrupted, the controller including: a phase detecting unit configured to detect a phase of a power supply voltage supplied from the alternating-current power supply , a gate signal generating unit configured to interrupt the gate signal when an open command is provided to the static switch and when the phase of the power supply voltage detected by the phase detecting unit matches a target phase, and a target phase setting unit configured to set the target phase based on a power factor angle of the load that is externally input, the target phase setting unit being configured to set a phase range where interruption of the gate signal is prohibited, based on the power factor angle of the load , so as to include a zero crossing point at which a load current is switched in polarity, and set the target phase outside of the phase range. a thyristor switch connected between the alternating-current power supply and the load and including a pair of arms connected in anti-parallel, each of the arms including a plurality of thyristors connected in series; and a controller configured to perform on-off control of the thyristor switch , the thyristor switch being configured to be turned on in response to a gate signal supplied from the controller , and turned off in response to a current coming to zero in a state in which the gate signal is interrupted, the controller including: a phase detecting unit configured to detect a phase of a power supply voltage supplied from the alternating-current power supply , a gate signal generating unit configured to interrupt the gate signal when an open command is provided to the static switch and when the phase of the power supply voltage detected by the phase detecting unit matches a target phase, and a phase detecting unit configured to detect a phase of a power supply voltage supplied from the alternating-current power supply , a gate signal generating unit configured to interrupt the gate signal when an open command is provided to the static switch and when the phase of the power supply voltage detected by the phase detecting unit matches a target phase, and a target phase setting unit configured to set the target phase based on a power factor angle of the load that is externally input, the target phase setting unit being configured to set a phase range where interruption of the gate signal is prohibited, based on the power factor angle of the load , so as to include a zero crossing point at which a load current is switched in polarity, and set the target phase outside of the phase range. <EOS>