A focusing
electrode plate, an extraction mechanism, an
ion beam generating device, and an
ion implanter are disclosed. The focusing
electrode plate includes a first channel penetrating the
electrode body, through which ions pass. The radial cross-section of the first channel is elongated, and the depth of the first channel is greater than or equal to the width of the entrance end of the first channel. As the depth of the first channel increases, the
potential difference between the entrance / exit of the first channel and the interior of the first channel increases, thereby improving the focusing effect on the
ion beam.