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The beam‐plasma type ion source that we have developed has an original ion‐ beam extraction mechanism. An ion beam is formed with an ion space‐charge compensation by electrons which are distributed by force in the extraction region. The electrons are used in order to ameliorate an ion space‐charge effect, which might be an obstacle for high‐current ion‐beam extraction. The space charge of ions is effectively neutralized by many kinds of energetic electrons; that is, a primary electron beam, a secondary electron beam, and high‐energy plasma electrons. When the ion space‐charge compensation by these electrons is effective, theoretically, the divergence of an ion beam is suppressed, the space‐charge limitation of an extractable ion current is relaxed, and the shape of the ion‐emission surface is improved. Therefore, a high‐current ion beam with good quality can be extracted, even at a low‐extraction voltage. In the experiment, the current of more than 0.1 A at the extraction voltage of 1–5 kV, which was more than ten times the normal space‐charge limited current, was extracted from a single aperture under the ion space‐charge compensation condition.