A vacuum packaging apparatus , comprising: a chamber that accommodates a packaging bag (B) in which a packaged object including a liquid is received; a degasifier that degasses inside the packaging bag (B) by decompressing inside the chamber ; a filling-opening closing device that is provided inside the chamber , the filling-opening closing device for opening and closing a packaged-object filling opening (Ba) of the packaging bag (B); a sealing device that seals the packaged-object filling opening (Ba) that is in a closed state; an inflation detection means that is capable of detecting a change of position of at least a part of the packaging bag (B) to a predetermined position, which is a position the part of the packaging bag (B) reaches when the liquid in the packaging bag (B) boils and the packaging bag (B) is inflated inside the chamber ; and a controller that controls the degasifier , the filling-opening closing device , and the sealing device , wherein: the controller controls the filling-opening closing device to close the packaged-object filling opening (Ba) of the packaging bag (B), controls the degasifier to perform decompression inside the chamber to a level at which the liquid boils, controls the filling-opening closing device to open the packaged-object filling opening (Ba) and controls the degasifier to stop degassing when the inflation detection means detects a change of position of at least a part of the packaging bag (B) to the predetermined position, and controls the sealing device to seal the packaged-object filling opening (Ba). a chamber that accommodates a packaging bag (B) in which a packaged object including a liquid is received; a degasifier that degasses inside the packaging bag (B) by decompressing inside the chamber ; a filling-opening closing device that is provided inside the chamber , the filling-opening closing device for opening and closing a packaged-object filling opening (Ba) of the packaging bag (B); a sealing device that seals the packaged-object filling opening (Ba) that is in a closed state; an inflation detection means that is capable of detecting a change of position of at least a part of the packaging bag (B) to a predetermined position, which is a position the part of the packaging bag (B) reaches when the liquid in the packaging bag (B) boils and the packaging bag (B) is inflated inside the chamber ; and a controller that controls the degasifier , the filling-opening closing device , and the sealing device , wherein: the controller controls the filling-opening closing device to close the packaged-object filling opening (Ba) of the packaging bag (B), controls the degasifier to perform decompression inside the chamber to a level at which the liquid boils, controls the filling-opening closing device to open the packaged-object filling opening (Ba) and controls the degasifier to stop degassing when the inflation detection means detects a change of position of at least a part of the packaging bag (B) to the predetermined position, and controls the sealing device to seal the packaged-object filling opening (Ba). controls the filling-opening closing device to close the packaged-object filling opening (Ba) of the packaging bag (B), controls the degasifier to perform decompression inside the chamber to a level at which the liquid boils, controls the filling-opening closing device to open the packaged-object filling opening (Ba) and controls the degasifier to stop degassing when the inflation detection means detects a change of position of at least a part of the packaging bag (B) to the predetermined position, and controls the sealing device to seal the packaged-object filling opening (Ba). <EOS>