A newly devised single shear test has been developed for metal powder compact. A special particular compaction method was suggested to produce the powder compact as specimen. By this method, even though the high normal pressure is applied, it can be possible to shear the powder compact at single plane that is parallel to the shear direction. In this test the normal stress and shear stress at shear plane were measured directly, failure criteria for iron powder compact and its dilatancy characteristics have also been evaluated. The shear stress increases with increasing normal stress and becomes larger for higher density ratio. The critical state line was also evaluated as the relation between normal stress and shear stress at the boundary of dilation and consolidation during shear.