An air-conditioning apparatus , comprising: a refrigerant circuit in which a compressor , an indoor heat exchanger , an expansion device , an outdoor heat exchanger , and a switching device configured to switch operation to a heating operation or a defrosting operation are connected by a refrigerant pipe to circulate refrigerant; an outdoor pipe temperature sensor configured to measure an outdoor refrigerant temperature; a temperature sensor located in a vicinity of at least one of an outlet and an inlet of the indoor heat exchanger in the refrigerant circuit , the temperature sensor being provided in an area adjacent to a seam in the refrigerant pipe; and characterized in that the air- conditioning apparatus further comprises: a controller configured to determine presence of refrigerant leakage on a basis of a decrease in temperature measured by the temperature sensor , when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is higher than the temperature measured by the temperature sensor , the controller being configured to determine presence of refrigerant leakage during a period in which the defrosting operation is performed, and when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is equal to or lower than the temperature measured by the temperature sensor , the controller being configured to stop determination of presence of refrigerant leakage during the period in which the defrosting operation is performed. a refrigerant circuit in which a compressor , an indoor heat exchanger , an expansion device , an outdoor heat exchanger , and a switching device configured to switch operation to a heating operation or a defrosting operation are connected by a refrigerant pipe to circulate refrigerant; an outdoor pipe temperature sensor configured to measure an outdoor refrigerant temperature; a temperature sensor located in a vicinity of at least one of an outlet and an inlet of the indoor heat exchanger in the refrigerant circuit , the temperature sensor being provided in an area adjacent to a seam in the refrigerant pipe; and characterized in that the air- conditioning apparatus further comprises: a controller configured to determine presence of refrigerant leakage on a basis of a decrease in temperature measured by the temperature sensor , when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is higher than the temperature measured by the temperature sensor , the controller being configured to determine presence of refrigerant leakage during a period in which the defrosting operation is performed, and when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is equal to or lower than the temperature measured by the temperature sensor , the controller being configured to stop determination of presence of refrigerant leakage during the period in which the defrosting operation is performed. a controller configured to determine presence of refrigerant leakage on a basis of a decrease in temperature measured by the temperature sensor , when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is higher than the temperature measured by the temperature sensor , the controller being configured to determine presence of refrigerant leakage during a period in which the defrosting operation is performed, and when the outdoor refrigerant temperature measured by the outdoor pipe temperature sensor is equal to or lower than the temperature measured by the temperature sensor , the controller being configured to stop determination of presence of refrigerant leakage during the period in which the defrosting operation is performed. <EOS>