Abstract: A material piece scooping device, which extracts a material piece from a surface of an object to be scooped by cutting electric discharges between an electric discharge electrode and the object to be scooped, includes a rotation drive section 40, an arm portion 30 driven by the rotation drive section to rotate around a rotational axis X, an electrode holder 20 supported by the arm portion, and an electric discharge electrode 10 detachably mounted on the electrode holder. A sliding section for sliding the arm portion in a direction perpendicular to the rotational axis and an arm length adjusting section for adjusting a length of the arm portion from the rotational axis thereof are provided, so as to adjust a trajectory of the electric discharge electrode as the arm portion rotates. The material piece can be scooped from the object along a line of the trajectory gnawing into the object.