An air conditioner in which a compressor, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger are connected to one another through pipes (31, 32) to configure a ring-shaped refrigerant circuit, an outdoor unit includes the compressor, the outdoor heat exchanger and the expansion valve, an indoor unit includes the indoor heat exchanger, and the outdoor unit and the indoor unit are connected to each other through a liquid-side connection pipe and a gas-side connection pipe to configure the refrigerant circuit, wherein the air conditioner includes a refrigerant charge port provided in a connection valve (14, 15) connected to the liquid-side connection pipe or the gas-side connection pipe, a liquid-side valve provided on the pipe between the liquid-side connection pipe and the expansion valve, and a gas-side valve provided on the pipe between the gas-side connection pipe and the compressor, wherein the air conditioner further includes a pressure detector provided on the pipe from the liquid-side valve to the indoor heat exchanger or the pipe from the indoor heat exchanger to the gas-side valve, a degree of vacuum setting means and comparison means, and a control unit which, in a state where the outdoor unit contains the refrigerant precharged into the pipe of the outdoor unit closed by the liquid-side valve and the gas-side valve, where the liquid-side valve and the gas-side valve are closed, where the outdoor unit and the indoor unit are connected to each other, and where evacuation is carried out by a vacuum pump connected to the opened refrigerant charge port, closes the refrigerant charge port, and opens the liquid side valve and the gas-side valve when the pressure detector detects a predetermined degree of vacuum, wherein, as the evacuation operation is carried out, a detection signal from the pressure detector is sent to the control unit, and the comparison means compares whether a degree of vacuum reaches a value set by the degree of vacuum setting means. the air conditioner includes a refrigerant charge port provided in a connection valve (14, 15) connected to the liquid-side connection pipe or the gas-side connection pipe, a liquid-side valve provided on the pipe between the liquid-side connection pipe and the expansion valve, and a gas-side valve provided on the pipe between the gas-side connection pipe and the compressor, wherein the air conditioner further includes a pressure detector provided on the pipe from the liquid-side valve to the indoor heat exchanger or the pipe from the indoor heat exchanger to the gas-side valve, a degree of vacuum setting means and comparison means, and a control unit which, in a state where the outdoor unit contains the refrigerant precharged into the pipe of the outdoor unit closed by the liquid-side valve and the gas-side valve, where the liquid-side valve and the gas-side valve are closed, where the outdoor unit and the indoor unit are connected to each other, and where evacuation is carried out by a vacuum pump connected to the opened refrigerant charge port, closes the refrigerant charge port, and opens the liquid side valve and the gas-side valve when the pressure detector detects a predetermined degree of vacuum, wherein, as the evacuation operation is carried out, a detection signal from the pressure detector is sent to the control unit, and the comparison means compares whether a degree of vacuum reaches a value set by the degree of vacuum setting means.