Elastgraphy is new technology in breast ultrasound examination and there are many methodology and the interpretations. Real time tisuue elastography（RTE）was introduced in 2003，we have used RTE for many cases and it helped us more information than fundermental B-mode examinations. More Recently Shear wave elastography（SWE）tecnology was improved and bringing quantative diagnostic capability. 【Purpose】 To evaluate various normal breast tissues stiffuness by SWE, and compare RTE and SWE in benign and malignant breast lesions. 【Material and Methods】 We examined 16 wemon for normal breast tissue elastisy by SEW（Aplio 500 Toshiba Medical systems）, we examined SWE and RTE（Accendus Hitachi Aloka Medical Systems）of 23 fibroadenoma, 11 DCIS, and 33 invasive ductal carcinoma. 【Result】 Shear wave velocity in normal breast tissue was 1.21〜3.1m/sec, but it is affected by probe compression. Velosity of the lesions are 3.34（1.80〜6.90）m/sec in FA, 3.18（2.05〜5.33）m/sec in DCIS and 4.51（1.83〜7.11）m/sec in invasive carcinomas respectively. One of FA case showed 5.33m/sec of which showed pathologically old FA. 【Discussion】 SWE can measure tissue stiffness and will be useful tool for measure normal breast tissue densities and breast differencial diagnosis, but still further investigations are needed for such as probe compression method, result difference between the machines.