A vitreous body cutter that allows wide movement of an opening position at the end part of a pipe even when the pipe is thin and that allows suction of vitreous bodies etc. in a wide range. The vitreous body cutter includes: a pipe having an opening on the side of an end part； a cutter, which slides along the inner surface of the pipe； a power output section, which is connected to the pipe and slides the cutter； and an outer case, through which the pipe passes, and which includes the power output section inside； and further includes a joint for connecting the outer case to a cannula attached to an eyeball. The protrusion length of the pipe from the outer case can be changed.
