Edge shape measurement apparatus and method of measuring edge shape

An edge shape measurement apparatus comprising:

• a displacement sensor configured to measure an edge shape of a wafer having a plate like shape, wherein
• the displacement sensor has a configuration of being rotationally driven setting a predetermined point inside the wafer as a rotational center in a plane which includes the rotational center, and is perpendicular to upper and lower surfaces of the wafer while keeping a constant radius with respect to the rotational center, and
• has a configuration of measuring a distance to one point on a surface of the wafer located on a straight line connecting the rotational center and the displacement sensor by a rotational angle;
• and
• a first controller having a positioning unit, wherein the positioning unit is configured to adjust the rotational center and a rotation range of the displacement sensor so that distances from the displacement sensor to an upper surface and a lower surface of the wafer are predetermined distances, and the edge shape of the wafer, which is included in a range determined in advance by a user, and a measurement range from an end point of the wafer toward a center of the wafer, can be measured.