An air-conditioning apparatus comprising: a compressor, an outdoor heat exchanger, an expansion unit and an indoor heat exchanger connected, by pipes, in a refrigerant circuit through which refrigerant flows; an outdoor fan configured to send outdoor air to the outdoor heat exchanger; and a controller configured to control operations of the outdoor fan, characterized in that the controller has a voltage acquisition unit configured to acquire drive voltages of the outdoor fan at set time intervals while a rotation speed of the outdoor fan is maintained at a reference rotation speed, a determination unit configured to determine whether or not a drive voltage acquired by the voltage acquisition unit is equal to or greater than a lower limit threshold and less than an upper limit threshold, an extraction unit configured to calculate an evaluation value by extracting a drive voltage determined, by the determination unit, to be equal to or greater than the lower limit threshold and less than the upper limit threshold, and a defrosting determination unit configured to decide to defrost the outdoor heat exchanger when the evaluation value calculated by the extraction unit is equal to or greater than an evaluation threshold. a compressor, an outdoor heat exchanger, an expansion unit and an indoor heat exchanger connected, by pipes, in a refrigerant circuit through which refrigerant flows; an outdoor fan configured to send outdoor air to the outdoor heat exchanger; and a controller configured to control operations of the outdoor fan, characterized in that the controller has a voltage acquisition unit configured to acquire drive voltages of the outdoor fan at set time intervals while a rotation speed of the outdoor fan is maintained at a reference rotation speed, a determination unit configured to determine whether or not a drive voltage acquired by the voltage acquisition unit is equal to or greater than a lower limit threshold and less than an upper limit threshold, an extraction unit configured to calculate an evaluation value by extracting a drive voltage determined, by the determination unit, to be equal to or greater than the lower limit threshold and less than the upper limit threshold, and a defrosting determination unit configured to decide to defrost the outdoor heat exchanger when the evaluation value calculated by the extraction unit is equal to or greater than an evaluation threshold. a voltage acquisition unit configured to acquire drive voltages of the outdoor fan at set time intervals while a rotation speed of the outdoor fan is maintained at a reference rotation speed, a determination unit configured to determine whether or not a drive voltage acquired by the voltage acquisition unit is equal to or greater than a lower limit threshold and less than an upper limit threshold, an extraction unit configured to calculate an evaluation value by extracting a drive voltage determined, by the determination unit, to be equal to or greater than the lower limit threshold and less than the upper limit threshold, and a defrosting determination unit configured to decide to defrost the outdoor heat exchanger when the evaluation value calculated by the extraction unit is equal to or greater than an evaluation threshold.