Patent ID: 8758251

Claim:
An ultrasound endoscope, comprising: an electronic scan type ultrasound transducer having an array of ultrasound elements mounted on a rigid tip end section of an endoscopic insert section in an axial direction thereof; an instrument outlet of a biopsy channel opened in a casing of said rigid tip end section in an obliquely upward direction from behind said ultrasound transducer for protruding a medical instrument into a body cavity, and an inclined casing wall section provided further on a rear side of said instrument outlet for fitting optical observation means including two illumination windows and an image pickup assembly provided between said two illumination windows; and a plateau provided on said rigid tip end section between said ultrasound transducer and said inclined casing wall section, wherein receded light guide walls facing lateral directions are provided on opposite lateral sides of said plateau, said receded light guide walls are formed by obliquely cutting opposite lateral sides of said plateau on said rigid tip end section, and front corner portions of said plateau are cut off to provide cutback walls each fitted with an additional illumination window.