An ultrasonic diagnostic apparatus configured to transmit an ultrasonic wave to the interior of a subject, receive the reflected wave from a living body tissue, obtain an ultrasonic tomographic image in the interior of the subject, while obtaining an endoscopic optical image in the interior of the subject, and to display at least one of the ultrasonic tomographic image and the endoscopic optical image on a monitor, the ultrasonic diagnostic apparatus comprising: first region display means for displaying one of the ultrasonic tomographic image or the endoscopic optical image in a first display region of the display screen of the monitor; second region display means for displaying the endoscopic optical image in a second display region on a part of the display screen of the monitor; characterized in that the ultrasonic diagnostic apparatus is further configured to obtain and display a blood flow dynamic state image and further comprises: third region display means for superimposing the blood flow dynamic state image in a third display region on the ultrasonic tomographic image displayed in the first display region on the display screen of the monitor; switching means for switching between the ultrasonic tomographic image and the endoscopic optical image displayed on the monitor by the first region display means while switching so as to display the endoscopic optical image by the second region display means and/or the blood flow dynamic state image by the third region display means when the ultrasonic tomographic image is displayed by the first region display means; image quality adjusting means for adjusting luminance and chroma of an image displayed on the monitor by the first region display means, the second region display means, and the third region display means respectively; image quality adjustment data storing means for storing adjustment contents of the image quality adjusting means; and image adjustment interlocking means for interlocking operations of the switching means and the image quality adjustment means; wherein adjusting luminance and chroma suitable for the display image switched by the switching means to be displayed on the monitor are switched synchronized with the switching of signals to be displayed on the monitor by the switching section. first region display means for displaying one of the ultrasonic tomographic image or the endoscopic optical image in a first display region of the display screen of the monitor; second region display means for displaying the endoscopic optical image in a second display region on a part of the display screen of the monitor; characterized in that the ultrasonic diagnostic apparatus is further configured to obtain and display a blood flow dynamic state image and further comprises: third region display means for superimposing the blood flow dynamic state image in a third display region on the ultrasonic tomographic image displayed in the first display region on the display screen of the monitor; switching means for switching between the ultrasonic tomographic image and the endoscopic optical image displayed on the monitor by the first region display means while switching so as to display the endoscopic optical image by the second region display means and/or the blood flow dynamic state image by the third region display means when the ultrasonic tomographic image is displayed by the first region display means; image quality adjusting means for adjusting luminance and chroma of an image displayed on the monitor by the first region display means, the second region display means, and the third region display means respectively; image quality adjustment data storing means for storing adjustment contents of the image quality adjusting means; and image adjustment interlocking means for interlocking operations of the switching means and the image quality adjustment means; wherein adjusting luminance and chroma suitable for the display image switched by the switching means to be displayed on the monitor are switched synchronized with the switching of signals to be displayed on the monitor by the switching section. third region display means for superimposing the blood flow dynamic state image in a third display region on the ultrasonic tomographic image displayed in the first display region on the display screen of the monitor; switching means for switching between the ultrasonic tomographic image and the endoscopic optical image displayed on the monitor by the first region display means while switching so as to display the endoscopic optical image by the second region display means and/or the blood flow dynamic state image by the third region display means when the ultrasonic tomographic image is displayed by the first region display means; image quality adjusting means for adjusting luminance and chroma of an image displayed on the monitor by the first region display means, the second region display means, and the third region display means respectively; image quality adjustment data storing means for storing adjustment contents of the image quality adjusting means; and image adjustment interlocking means for interlocking operations of the switching means and the image quality adjustment means; wherein adjusting luminance and chroma suitable for the display image switched by the switching means to be displayed on the monitor are switched synchronized with the switching of signals to be displayed on the monitor by the switching section.