1. An ultrasound diagnosis apparatus having an ultrasound probe in which a plurality of transducer elements are arrayed, and which converges and radiates an ultrasound on a patient and detects a reflection wave thereof; and imaging a tomogram of the patient, using the reflection wave, the apparatus comprising: an operation means for performing a pattern matching between the tomogram imaged with one frame and the tomogram imaged with another frame and operating a displacement image; and a tissue expansion detector for performing another pattern matching between the displacement image and a displacement function for expressing a displacement form caused by a partial tissue expansion of the patient, wherein a tissue expansion generated at a part of the patient is extracted from the tomogram according to the another pattern matching.