A compressed granular system was divided into two kinds of zones, so-called "plastic" zone and "elastic" one. The "elastic" zone has no intergrain slip, while the "plastic" zone has it. In the "elastic" zone the force distribution around the grains was assumed to be similar to the stress ellipsoid, and the relations between the stress components and the principal values of the force distribution around the grains were derived. Furthermore the stress-strain relations in the "elastic" zone were obtained, taking translation, rotation and local deformation of granules into consideration.