Abstract: An axial sealing mechanism of a volute compressor comprises a fixed volute member, a orbiting volute member, and an isolating member which is fastened to the back of the fixed volute member and provided with back pressure chambers into which an intermediate-pressure working fluid or a high-pressure working fluid is introduced via the compression chambers formed by the fixed volute member and the orbiting volute member. The pressing member in the back pressure chamber is therefore forced to urge axially the fixed volute member so as to overcome the axial thrust and the overturn moment of force, which exert on the fixed volute member at the time when the compression chambers are in operation. The axial gap between the fixed volute member and the orbiting volute member is thus minimized so as to prevent the working fluid from leaking out from the compression chambers and to improve the volumetric efficiency of the volute compressor.