When scanning a three-dimensional region while rotating a scanning plane about a predetermined axis (rotation axis), an ultrasonic diagnostic apparatus calculates a motion vector of a motion scanning plane (ultrasonic sectional layer) using ultrasonic image data in the rotation axis and corrects a positional mismatch between the scanning planes using the calculated motion vector. The motion vector is calculated and the positional mismatch between the sectional layers, using at least one frame having a cardiac time phase close to the frame of which the motion should be corrected and being spatially close to the frame, in addition to the frames at the same cardiac time phase as the frame of which the motion should be corrected.