Disclosed is an ultrasound diagnostic imaging apparatus which displays an ultrasound image on a display screen of a display unit based on ultrasound image data. The ultrasound diagnostic imaging apparatus includes a touch panel and a control unit. The control unit is able to execute a vertical display mode to display two ultrasound images aligned vertically on the display screen and a horizontal display mode to display two ultrasound images aligned horizontally on the display screen. In each display mode, the control unit sets operation reception regions aligned vertically or horizontally on the touch panel. When the control unit detects an operation of touching one of the operation reception regions, the control unit sets an ultrasound image displayed in the touched side to a selected state.