Measuring apparatus

A measuring apparatus comprising:

• a reference member held in fixed position and orientation with respect to a workpiece during measurement;
• a stylus for scanning a surface of the workpiece while being displaced upward and downward in accordance with unevenness of the surface of the workpiece;
• a displacement gauge for measuring a displacement of a specific part of the stylus relative to the reference member;
• and
• a scanner for causing the stylus to scan the workpiece along the surface;
• wherein the fixed position and orientation of the reference member with respect to the workpiece are not changed even during the operation of the scanner;
• the up-and-down displacement of the specific part of the stylus is measured relative to the reference member;
• a fine shape of the workpiece is detected in accordance with the measured displacement of the specific part of the stylus,
• wherein the scanner scans the workpiece and the reference member with respect to the stylus and the displacement gauge or causes the stylus and the displacement gauge to travel with respect to the workpiece and the reference member during measurement while a displacement axis representing the direction of the up-and-down displacement of the stylus and a measurement axis along which the displacement gauge measures the displacement of the specific part of the stylus are kept coincident with each other.