[en] In an actual inertial fusion reactor, a fuel target alignment error may happen; the target alignment error induces heavy ion beam illumination non-uniformity on the target. The beam illumination non-uniformity leads a degradation of fusion energy output. On the other hand, heavy ion beam accelerator provides a capability to oscillate beam axis with a high frequency. The wobbling beams may provide a new method to reduce or smooth the beam illumination non-uniformity. In this paper, we focus on the wobbler illumination non-uniformity onto a spherical target. We found that the tolerable displacement of the target illuminated by the wobbling ion beams is about 80 ∼ 90 μm in a fusion reactor. (author)