【Purpose】 Strain Elastography is a useful tool to know the rigidity of breast mass, and the strain ratio is important for the transplantation as well as Tsukuba Score. But the strain elastography have some bias against the reliability because of the process to make images, maneuver（compression etc.）, subjective selection of the phase to calculate, Targeting of the mass ROI and fat ROI. For the strain ratio to be more reliable, we have devised a new application with some resolution for these bias, and have done a preliminary study in our institute. Methods and Materials: We made “Auto Strain Ratio System（ASR）” with no manual compression and auto phase selection, auto ROI targeting system. These were made from some new algorithm and skilled doctor’s AI data. 232 breast mass in our institute with manual strain ratio（MSR）by professional doctors and ASR together have been enrolled to this study and evaluated prospectively. 【Results】 MSR is 3.06+/-1.99（average+/-standard deviation）in benign lesions, MSR is 8.19+/-4.95 in malignant lesions, ASR is 2.42+/-1.50 in benign lesions, ASR is 6.99+/-4.32 in malignant lesions. 【Conclusion】 It seems that the ASR is more reliable than MSR because of the small deviation and similar average of each data. The ASR gives us an easy process and a high quality control to evaluate elastography with small bias in examination.