Ultrasonic endoscope

1. An ultrasonic endoscope comprising:

an insertion portion including;

an angle portion;

a hard distal portion coupled to the angle portion;

an endoscopic observation unit comprising a lighting portion and an observation portion, the endoscopic observation unit being located at the hard distal portion; and

an ultrasonic test unit comprising an ultrasonic transducer constituting an ultrasonic test unit, the ultrasonic test unit being located at the hard distal portion, wherein

the ultrasonic transducer is located at a tip end of the hard distal portion, the hard distal portion comprises a sloping face that is obliquely tilted from a portion whereat the ultrasonic transducer is attached to a base end of the hard distal portion, and the endoscopic observation unit is attached to the sloping face,

the hard distal portion further including,

an elevator including an elevation operating unit for a treatment equipment and a treatment equipment guide movably connected within the distal portion to be elevated by the elevation operating unit, the treatment equipment guide having a head portion located at a position preceding the endoscopic observation unit and behind the ultrasonic transducer, the treatment equipment guide being laterally offset with respect to the observation unit, and

the hard distal portion including,

a distal end main body including an entire portion whereat the ultrasonic transducer is attached;

an observation portion block that includes a portion whereat the observation portion is attached and that is separably coupled with the distal end main body; and

an elevator block that is securely held between the distal end main body and the observation portion block by engaging the distal end main body and the observation portion block, and that comprises the elevator, and

the distal end main body, the observation portion block and the elevator block of the hard distal portion are reversibly assembled.

2. An ultrasonic endoscope according to claim 1 , wherein a coupling ring is fitted to a portion, adjacent to the base end of the hard distal portion, whereto the distal end main body and the observation unit are joined.

3. An ultrasonic endoscope according to claim 1 , wherein the observation portion block further comprises a first engagement portion, and the elevator block further comprises a second engagement portion, and

wherein the distal end main body further comprises a recessed portion into which the first and second engagement portions are substantially tightly fitted.

4. An ultrasonic endoscope according to claim 1 , wherein the observation portion comprises an observation unit that includes an object optical system, a prism and a solid-state imaging device,

wherein the observation portion block further comprises a recessed portion that is open on a side which contacts the distal end main body, and the observation unit is detachably fitted in the recessed portion, and

wherein the observation portion block further comprises: a path having a semicircular cross section at a portion whereat the observation portion block and the distal end main body contact each other; and a light guide mounted to the lighting portion, the light guide being attached to the path.