The invention is to provide an ultrasonic image with a clear tissue structure while reducing speckle noise of the ultrasonic image. An ultrasonic wave is transmitted from the transducer to the subject, and an echo generated in the subject is received. The first ultrasonic image and the second ultrasonic image are generated using a reception signal. The second ultrasonic image is an image smoother than the first ultrasonic image. The image processing unit calculates filter coefficients using pixel values of corresponding pixels of the first ultrasonic image and the second ultrasonic image, and generates an output image by processing one of the first ultrasonic image and the second ultrasonic image using the filter coefficients.
