1. A medical image diagnosis device comprising: an image generating means configured to obtain image data of a tissue of an object and generate an image of the tissue of the object based on the image data; a calculation means configured to calculate at least one of brightness and motion vectors of a plurality of measurement points of the generated image; an input means configured to specify an observation region of the image; a database in which a characteristic amount of at least one of the brightness and the motion vectors of the measurement points in respective images of a plurality of different observation regions is set and stored in advance; a checking means configured to read the characteristic amount of the observation region that is specified through the input means from the database and check the characteristic amount with results of calculation performed on the generated image by the calculation means; and an ROI setting means configured to set a region of interest in the generated image based on the checked results of the checking means.