PURPOSE: To obtain large acceleration with a small device by providing a movable conductor wherein one end is rotated along a central shaft electrode and the other end is movable along a spiral electrode to provide the movable conductor with an attached part for separably supporting a flying object on the movable conductor, and a high voltage power source device is connected between the central shaft electrode and the spiral electrode.

CONSTITUTION: A movable conductor 8 is positioned at the lower end part of a central shaft electrode 4 to engage a projection lock part 11 in a lock groove 12 of an attached part 10 so as to separately attach a flying object 9 to the movable conductor 8. A switch 15 is turned on to impress a high voltage of a high voltage power source device 14 between the central shaft electrode 4 and a spiral electrode 5. The movable conductor 8 and the flying object 9 are guided in the spiral electrode 5 and the central shaft electrode 4 by the use of Lorentz's force so as to accelerate as ascended. A magnetic field (B) is strengthened as the number of circumference times of the movable conductor 8 and the flying object 9 increase to increase generating Lorentz's force so as to increase acceleration. The movable conductor 8 touches on a stopper 16 to stop rotating to separate the flying object 9 from the attached part 10 of the movable conductor 8 by the inertia to object so as to fly in the direction of an extension line on the upper end of the spiral electrode 5.