PURPOSE:To improve the magnetic adsorbing force by supporting a movable permanent magnet on a movable body such that the magnetic pole face will face against the magnetic pole member of a face plate while slidably thereby reducing the leakage flux between the movable permanent magnet and the face plate. CONSTITUTION:Under excited state, one magnetic pole face of a movable permanent magnet 20 is contacting directly against the corresponding magnetic pole member 22, thereby the flux from the permanent magnet 20 to the magnetic pole member 22 and from the pole member 22 to the permanent magnet 20 will never pass through a chip in conventional chuck but flow directly. Consequently, the magnetic path is shortened to reduce the leakage flux, thus to function the magnetic force of the movable permanent magnet 20 effectively onto the face plate 14. As a result, the magnetic loss can be reduced when compared with the conventional chuck resulting in improvement of the magnetic adsorbing force of the face plate 14.
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