A power-source power factor control system comprising: a load apparatus (101, 102) that is connected to an AC power source and that is supplied with power from the AC power source; a power-source power factor measuring unit that is configured to measure the power-source power factor; a control signal generating unit that is configured to generate, based on a measurement result of the power-source power factor measuring unit and a target value about the power-source power factor of the AC power source, a control signal Fs for charging the operation state of the load apparatus (101, 102); an operation state control unit (101c, 102c) that is configured to control, based on the control signal Fs, an operation state of the load apparatus (101, 102); and a target value adjusting unit that is configured to adjust, based on the measurement result of the power-source power factor measuring unit, the target value, characterised in that the target value adjusting unit is configured to adjust, the target value by using an average value of the power-source power factor in a unit period for which the target value is adjusted, in a case where an average value of the power-source power factor in a first period of the unit period exceeds a reference value, the target value adjusting unit is configured to cause the target value in a second period following the first period of the unit period to be smaller than the target value in the first period, and in a case where the average value in the first period is below the reference value, the target value adjusting unit is configured to cause the target value in the second period to be larger than the target value in the first period. a load apparatus (101, 102) that is connected to an AC power source and that is supplied with power from the AC power source; a power-source power factor measuring unit that is configured to measure the power-source power factor; a control signal generating unit that is configured to generate, based on a measurement result of the power-source power factor measuring unit and a target value about the power-source power factor of the AC power source, a control signal Fs for charging the operation state of the load apparatus (101, 102); an operation state control unit (101c, 102c) that is configured to control, based on the control signal Fs, an operation state of the load apparatus (101, 102); and a target value adjusting unit that is configured to adjust, based on the measurement result of the power-source power factor measuring unit, the target value, characterised in that the target value adjusting unit is configured to adjust, the target value by using an average value of the power-source power factor in a unit period for which the target value is adjusted, in a case where an average value of the power-source power factor in a first period of the unit period exceeds a reference value, the target value adjusting unit is configured to cause the target value in a second period following the first period of the unit period to be smaller than the target value in the first period, and in a case where the average value in the first period is below the reference value, the target value adjusting unit is configured to cause the target value in the second period to be larger than the target value in the first period.