A portion of refrigerant that is discharged from an injection-type compressor (1) passes through a first by-pass pipe (21) and is supplied to an outdoor heat exchanger (9b) to be defrosted by way of a first flow path switching device (A), and a portion of the refrigerant supplied to the outdoor heat exchanger (9b) to be defrosted is caused to flow to a second by-pass pipe (31) by way of a second flow path switching device (B).
