An ultrasound diagnosis apparatus: in conjunction with change of a projection region using an operation part, changes a viewpoint to a position where a reference cross section is in front and the changed projection region is on the back; in conjunction with change of the viewpoint using the operation part, changes a region where the reference cross section is in front and the changed viewpoint is on the back to the projection region; in conjunction with change of a scanning region using the operation part, changes the viewpoint to a position where the reference cross section is in front and the changed scanning region is on the back; in conjunction with change of the viewpoint using the operation part, changes the scanning region to a region where the reference cross section is in front and the viewpoint is on the back; and then executes rendering.