Ultrasonic endoscope

An ultrasonic endoscope that is provided with a rigid distal end portion at a distal end of an elongated insertion portion, the rigid distal end portion comprising:

• an optical observation portion of a side-viewing type in which an objective window is directed to a side in an observation direction that is substantially orthogonal to a longitudinal direction of the insertion portion;
• a laterally open recess to which a distal end connecting portion of a treatment tool conduit that is arranged in the insertion portion is connected, so that a treatment tool inserted into the treatment tool conduit can protrude, the laterally open recess having a pair of side walls that are separated from each other in a width direction that is substantially orthogonal to the longitudinal direction and the observation direction, and being open in the observation direction;
• an elevator that is supported in the laterally open recess so as to be able to perform rising/falling operation around a shaft directed in the width direction, and sets a direction in which the treatment tool protrudes from the laterally open recess, using a top portion of the elevator that protrudes the most in the observation direction;
• and
• an ultrasonic probe configured to obtain an ultrasonic tomographic image via a wave transmission/reception face that comes into contact with a part to be observed;
• wherein with respect to the width direction, the optical observation portion is located on one side of a boundary side wall that is one of the pair of side walls of the laterally open recess, and the wave transmission/reception face of the ultrasonic probe is located on the opposite side,
• with respect to the longitudinal direction, the wave transmission/reception face is located in a range in which at least a part of the wave transmission/reception face overlaps the boundary side wall, and the wave transmission/reception face and the elevator are offset from each other, and
• when the rigid distal end portion is viewed from the side in the observation direction, the top portion of the elevator is located on a virtual line that connects a center of an outer shape of the wave transmission/reception face and a center, in the width direction, of the distal end connecting portion of the treatment tool conduit.