A biopsy treatment instrument according to the present invention includes a flexible sheath, an insertion portion capable of advancing and retracting in the flexible sheath, a recessed portion for specimen sampling provided on a side surface of the insertion portion, a capacitive ultrasound transducer array provided on a bottom surface of the recessed portion for specimen sampling, and a slide portion that relatively slides the insertion portion and the flexible sheath so that the recessed portion for specimen sampling opens and closes. It is determined on the basis of a reflected wave received by the capacitive ultrasound transducer array whether or not a specimen is captured into the recessed portion for specimen sampling. Therefore, it is possible to surely sample the specimen.
