Loading machine stiffness is considered in an attempt to simulate strain accumlation processes prior to failure in earthquakes. We impose the similarity condition that the inelastic deformation in a test specimen relative to the loading machine corresponds with that in a spherical seismic region relative to the surrounding earth. From this constraint the appropriate ratio between the stiffnesses of machine and specimen is determined to be 1.5~2.3. Preliminary experiments were carried out for sandstone samples. A qualitative difference between acoustic emission sequences was observed depending on whether the conditions were similar or dissimilar to the earth based on the scaling assumption. In the former cases, a subsidence in acoustic emission activity prior to the main fractures was clearly and systematically observed.