PURPOSE: To improve the cooling ability of bearings, etc., by providing bearing parts at outside parts in the radial direction between a fixed scroll and a turning scroll, and providing a sealing member formed in a sectional U-shape and for cutting a space communicated with a suction port against the inside of a casing at a part inner than the bearing parts in the radial direction.

CONSTITUTION: In a vacuum pump, a suction chamber A communicated with a suction port 19 and each compression chamber 18 and a chamber B in a casing 1 are isolated by a sealing member 21, and at the time of starting up, the chamber B side is under the atmospheric pressure condition and the pressure of the suction chamber A side becomes temporarily higher than the atmospheric pressure with the sucked air, and a turning scroll 6 is pressed by a bearing part 3B of a casing 3, and the scroll 8 and a back surface 7B of a mirror plate are slided to contact each other and while support the load in the thrust direction. When the chamber A side becomes under the negative pressure condition little by little, the turning scroll 6 is pressed by a bearing part 17 of a fixed scroll 13, and the bearing part 17 and a front surface 7A of the mirror plate are mutually slided to contact each other and support the load in the thrust direction. The oil liquid 25 of the chamber B is stroked by a disc 24 to be fed to between the mirror plate 7 and the bearing parts 3B and 17.