A vacuum roaster comprising: a chamber; a door cap formed on one side of the chamber so as to be opened or closed; a vacuum cap formed on an opposite side of the chamber; a basket spaced apart from an inner circumferential surface of the chamber, and including a basket door that is opened or closed for introduction and discharge of an object to be processed, wherein the basket is provided in an outer circumferential surface thereof with a discharge hole for discharging a byproduct of the object to be processed, which is generated while the object to be processed is being roasted, and wherein the discharge hole is formed to have a diameter within a range from 1 mm to 10 mm, and wherein the basket is provided thereunder with a dust box in which the byproduct of the object to be processed, which is discharged through the discharge hole, accumulates; a vacuum adjustment device for adjusting a vacuum state inside the chamber, wherein the vacuum adjustment device, through the discharge hole, sucks the air in the basket and sucks the air in the chamber internal space outside the basket to adjust the vacuum state of the entire inside of the chamber; a drive motor connected to the basket via a shaft for rotating the basket; a heater provided inside the chamber so as to be spaced apart from the basket; and a filter formed inside the chamber for removing fine dust contained in gas generated inside the chamber; wherein the vacuum adjustment device includes: a vacuum pump for suctioning air inside the chamber; a water trap formed on a movement path of the air suctioned by the vacuum pump for condensing and collecting moisture contained in the suctioned air; a vacuum gauge formed on the movement path for measuring a vacuum pressure inside the chamber; and a cooling coil formed in a coil shape for lengthening the movement path, the cooling coil serving to cool the air moving in the movement path. a chamber; a door cap formed on one side of the chamber so as to be opened or closed; a vacuum cap formed on an opposite side of the chamber; a basket spaced apart from an inner circumferential surface of the chamber, and including a basket door that is opened or closed for introduction and discharge of an object to be processed, wherein the basket is provided in an outer circumferential surface thereof with a discharge hole for discharging a byproduct of the object to be processed, which is generated while the object to be processed is being roasted, and wherein the discharge hole is formed to have a diameter within a range from 1 mm to 10 mm, and wherein the basket is provided thereunder with a dust box in which the byproduct of the object to be processed, which is discharged through the discharge hole, accumulates; a vacuum adjustment device for adjusting a vacuum state inside the chamber, wherein the vacuum adjustment device, through the discharge hole, sucks the air in the basket and sucks the air in the chamber internal space outside the basket to adjust the vacuum state of the entire inside of the chamber; a drive motor connected to the basket via a shaft for rotating the basket; a heater provided inside the chamber so as to be spaced apart from the basket; and a filter formed inside the chamber for removing fine dust contained in gas generated inside the chamber; wherein the vacuum adjustment device includes: a vacuum pump for suctioning air inside the chamber; a water trap formed on a movement path of the air suctioned by the vacuum pump for condensing and collecting moisture contained in the suctioned air; a vacuum gauge formed on the movement path for measuring a vacuum pressure inside the chamber; and a cooling coil formed in a coil shape for lengthening the movement path, the cooling coil serving to cool the air moving in the movement path. a vacuum pump for suctioning air inside the chamber; a water trap formed on a movement path of the air suctioned by the vacuum pump for condensing and collecting moisture contained in the suctioned air; a vacuum gauge formed on the movement path for measuring a vacuum pressure inside the chamber; and a cooling coil formed in a coil shape for lengthening the movement path, the cooling coil serving to cool the air moving in the movement path.