A deformation experiment of ringwoodite with a strain of 9% was achieved at 20 GPa and 1 700 K and at a strain rate of 3x10(-5) s(-1) using a deformation-DIA (D-DIA) apparatus and a multi-anvil 6-6 (MA 6-6) assembly. The crystallographic orientations of the deformed sample were successfully analyzed by the electron backscatter diffraction (EBSD) method, although any notable lattice-preferred orientation (LPO) was not observed presumably due to the insufficient strain in the present experiment. In this study, the deformation experiment on ringwoodite succeeded at P-T conditions consistent with the lower part of the mantle transition zone and at a controlled strain rate for the first time. The present study extended the pressure range of deformation experiments in the D-DIA apparatus from 16 GPa in our earlier study to 20 GPa at 1 700 K. The successful extension of the pressure range demonstrates potential importance of the D-DIA apparatus in studying rheological properties of minerals under the P-T conditions of the whole mantle transition zone.