The invention provides a linear ion bounding apparatus and an array structure thereof. The linear ion bounding apparatus comprises a pair of main radio frequency electrodes. The main radio frequency electrodes are extended axially and are disposed oppositely at the two sides of the central axis of the linear ion bounding apparatus. The pictures of various cross-sections vertical to the central axis of the main radio frequency electrodes are symmetrical to a main symmetry plane passing through the central axis. Radio frequency voltage with same phases is applied to the pair of main radio frequency electrodes. At least one main radio frequency electrode is equipped with an ion leading-out slot. At least one pair of auxiliary electrodes are disposed at the two sides of the pair of main radio frequency electrodes and are placed in such a way of dual to the main symmetry plane. At least one auxiliary electrode comprises finite symmetry planes. Minimum intersection angles more than 0 degree but less than 90 degrees are provided between each symmetry plane of the auxiliary electrode and the symmetry plane of the main radio frequency electrodes. By such manner, the quadrupole field component of the ion bounding radio frequency electric field in the ion bounding apparatus can be reinforced.