An image processing unit (20) performs resolution conversion processing on an ultrasound image obtained on the basis of a reception signal, to generate a plurality of resolution images having mutually different resolutions. Furthermore, the image processing unit (20) performs non-linear processing on a difference image obtained by comparing the plurality of resolution images with each other, to generate boundary components related to boundaries included in the image. Moreover, a boundary-enhanced image is generated by performing enhancement processing on the ultrasound image on the basis of the generated boundary components.
