PURPOSE: To surely extract meat oyster without damaging, by applying air pressure or water pressure from slightly opened gap of oyster shells to move oyster meat downward, inserting an upper cutter approximately to the eyes of scallops and oscillating the cutter to the left and right direction.

CONSTITUTION: An air pressure or water pressure means X is inserted into slightly opened gap of oyster shells A and A', air pressure or water pressure is applied to oyster meat to move the oyster meat C downward. Then, an upper cutter 1 is introduced approximately to the eyes of scallops B and the cutter 1 is oscillated along the inner wall surface of the oyster shells A through a drive source 2 to the left and right direction, to cut the eyes of scallops B.