In building railroad embankments, the compaction level is managed in terms of K_30-value obtained from the plate loading test at present. Even when K_30-value is larger than prescription value, however, the compaction level is low for some embankment materials. When the compaction level is low, embankments will settle because of train loads. Therefore, we performed rolling compaction tests by using gravel to study an appropriate embankment control method. As a result, we found that the K_30-value disperses to large extents when the compaction level is high and satisfies the prescription value when the D-value (the degree of compaction) is about 85%. This suggests that the method of controlling compaction with the K_30-value alone doesn't provide an appropriate guideline for compaction.