A welding power supply device (A1) comprising: an inverter circuit that converts DC power into AC power and outputs the AC power to a welding load; and a voltage superimposing circuit that superimposes a restriking voltage on an output to the welding load when a polarity of an output current of the inverter circuit switches, wherein the voltage superimposing circuit includes: a restriking capacitor to be charged with the restriking voltage; a charging circuit that charges the restriking capacitor with the restriking voltage; and a discharging circuit that discharges the restriking voltage charged in the restriking capacitor , wherein the charging circuit includes: a DC power supply that outputs DC voltage; and characterised in that the charging circuit further includes: a voltage booster that boosts a DC voltage of the DC power supply, wherein the charging circuit charges the restriking capacitor in a first state and a second state following the first state, the first state being a state in which the DC voltage of the DC power supply is directly applied to the restriking capacitor , the second state being a state in which the DC voltage boosted by the voltage booster is applied to the restriking capacitor . an inverter circuit that converts DC power into AC power and outputs the AC power to a welding load; and a voltage superimposing circuit that superimposes a restriking voltage on an output to the welding load when a polarity of an output current of the inverter circuit switches, wherein the voltage superimposing circuit includes: a restriking capacitor to be charged with the restriking voltage; a charging circuit that charges the restriking capacitor with the restriking voltage; and a discharging circuit that discharges the restriking voltage charged in the restriking capacitor , wherein the charging circuit includes: a DC power supply that outputs DC voltage; and characterised in that the charging circuit further includes: a voltage booster that boosts a DC voltage of the DC power supply, wherein the charging circuit charges the restriking capacitor in a first state and a second state following the first state, the first state being a state in which the DC voltage of the DC power supply is directly applied to the restriking capacitor , the second state being a state in which the DC voltage boosted by the voltage booster is applied to the restriking capacitor . a restriking capacitor to be charged with the restriking voltage; a charging circuit that charges the restriking capacitor with the restriking voltage; and a discharging circuit that discharges the restriking voltage charged in the restriking capacitor , wherein the charging circuit includes: a DC power supply that outputs DC voltage; and characterised in that the charging circuit further includes: a voltage booster that boosts a DC voltage of the DC power supply, wherein the charging circuit charges the restriking capacitor in a first state and a second state following the first state, the first state being a state in which the DC voltage of the DC power supply is directly applied to the restriking capacitor , the second state being a state in which the DC voltage boosted by the voltage booster is applied to the restriking capacitor . a voltage booster that boosts a DC voltage of the DC power supply, wherein the charging circuit charges the restriking capacitor in a first state and a second state following the first state, the first state being a state in which the DC voltage of the DC power supply is directly applied to the restriking capacitor , the second state being a state in which the DC voltage boosted by the voltage booster is applied to the restriking capacitor . <EOS>