According to one embodiment, an ultrasound diagnosis apparatus includes a tomographic image data generator, a blood flow information generator, a change detector, and a condition changing unit. The tomographic image data generator sequentially obtains tomographic image data of a subject for a plurality of times. The blood flow information generator performs processing on a reception signal based on signal processing conditions including a velocity threshold related to blood flow information of the subject to obtain the blood flow information. The change detector detects the magnitude of change in the time axis direction of a plurality of pieces of tomographic image data for different times. The condition changing unit changes the signal processing conditions based on the magnitude of change in the time axis direction. When the signal processing conditions are changed, the blood flow information generator performs the processing based on changed signal processing conditions.