The invention relates to cryosurgical instrument for obtaining a tissue sample using a probe, wherein the probe comprises a probe head for freezing tissues, a probe shaft for advancing the probe head to the tissue, a feeding device for feeding a fluid into an expansion chamber and a conducting device. The conducting device is connected to the expansion chamber for delivering the expanded fluid out of the expansion chamber. The expansion of the fluid in the expansion chamber chills the probe head such that the tissue freezes to the probe head. Such surgical instruments can also be used according to the invention in thin hollow organs, such as gall bladder or pancreatic ducts, in order to obtain tissue samples. In said area of application, however, certain requirements are placed on the dimensions of the probe that could not be met by conventional probes. The present invention solves said problem in that the delivery device comprises at least one opening at the distal region of the probe, said opening conducting the fluid into an external region outside of the probe. According to the invention, a part of the expanding gas is thereby discharged directly into the hollow organ.