VACUUM CAPACITOR

[Object] An object of the present invention is to provide a vacuum capacitor, a vacuum state of a vacuum chamber of which is maintained without bellows etc., and whose capacitance is easily adjustable, and a decrease of life of which is lessened. [Means to solve] A fixed electrode 4 is formed by arranging a plurality of flat electrode members 5 in layers at a certain distance in an axial direction of a vacuum chamber 1b in the vacuum chamber 1b. A movable electrode 7 is an electrode that is formed by arranging a plurality of flat electrode members 8 in layers at a certain distance at a movable electrode shaft 9 in the vacuum casing 1, and by rotation of the movable electrode shaft 9, the each electrode member 8 of the movable electrode 7 is inserted into and extracted from a gap between the electrode members 5 of the fixed electrode 4 and alternately overlaps the electrode member 5 of the fixed electrode 4 with the each electrode member 8 of the movable electrode 7 in noncontact with the electrode members 5 of the fixed electrode 4. A magnetic flux receiving unit 12 is fixed to the movable electrode shaft 9 at a seal member 3 side in the vacuum casing 1, and a capacitance control unit 14 having a magnetic flux generating unit 13 is rotatably supported outside the seal member 3. By rotating the capacitance control unit 14 also rotating the magnetic flux receiving unit 12 by magnetic attraction, an overlap area between the movable electrode 7 and the fixed electrode 4 is changed, then capacitance adjustment is made.