A general-light observation light image can be obtained by illuminating the polarized frame sequence light or polarized white light, for example. In addition, a parallel polarized component and a vertical polarized component with respect to a polarizing direction of illuminating light, which is polarized in a specific direction are captured. Then, image data, which is a difference between both of the polarized component is calculated and is displayed in a display device. Thus, a scattered light component in a living-body tissue surface side can be extracted with good S/N, which can improve the diagnosis functionality.