An air conditioner and method of detecting a 
refrigerant leakage in the air conditioner in which the entire 
refrigerant pipe of the air conditioner is sectioned based on expansion valves into a plurality of sections, the sections are checked one by one to quickly detect a 
refrigerant leakage from the sections and an exact position of a broken or loosened area of the refrigerant 
pipe causing such a refrigerant leakage is found. In the method of detecting a refrigerant leakage in the air conditioner, comprising a compressor, an expansion valve, an outdoor 
heat exchanger, and an indoor 
heat exchanger connected to one another by a refrigerant 
pipe, the refrigerant pipe is sectioned into a 
high pressure section extending from the outlet port of the compressor to the inlet port of the expansion valve, and a low pressure section extending from the outlet port of the expansion valve to the inlet port of the compressor. A 
pressure sensor is provided on the refrigerant pipe within the low pressure section. A 
control unit detects a refrigerant leakage in the low pressure section by comparing a variation in refrigerant pressure sensed by the 
pressure sensor with a preset variation in the refrigerant pressure in accordance with a normal operation without the refrigerant pipe having a refrigerant leakage, during a refrigerant leakage detection mode.