To completely transfer the contents in a bag into a container or the like in a bag unsealing device and protect a human body, particularly a respiratory organ system, from the infiltration of dust generated when the bag is unsealed.

A bag unsealing device is provided with a mounting stand constituted of two tables 31a and 31b, left and right, set through a clearance 30 in the interior of the device, wherein the pressure is set negative, and revolved between the posture of lowering the edges facing each other and the horizontal posture of the tables 31a and 31b. A bag press section pressing the bags by a pressing pawl and revolved integrally with the tables 31a and 31b is set above the mounting stand, and a revolving blade 4 moved relatively along the clearance 30 is provided on the extension of the clearance 30. The bags are cut by moving the mounting stand toward the revolving plate 4. Then the tables 31a and 31b, left and right, are opened and closed several times to the lower side. A content is discharged while the empty bags are fixed on the tables 31a and 31b by the above operation.