[Problem] Provided are: a fragmentation tip able to suppress the occurrence of cavitation； an intraocular surgery device； a method for suppressing the occurrence of cavitation； and a cataract surgery method. [Solution] The fragmentation tip is attached to an intraocular surgery device that imparts ultrasonic vibrations, and is provided with: a tubular support section mounted to the intraocular surgery device； and a tubular tip main body that is provided to the tip of the support section and that interconnects with the inner space of the support section. The tip main body has a cross-sectional shape such that the length in a first direction is longer than the length in a second direction perpendicular thereto. Vibrations are imparted to the support section in a manner so that the tip main body reciprocally rotates around the axial line of the tip main body passing through the center in the first direction and second direction.
