There is provided a roughness tester that improves measurement efficiency and roughness measurement accuracy.
A roughness tester includes a stylus unit including a stylus that is provided in such a manner as to protrude from and retract into a through hole of a skid and performs scanning movement along a surface of a workpiece, and a stylus displacement detecting unit that detects displacement of the stylus, and a drive unit that moves the stylus unit forward and backward in a drive-axis direction. The roughness tester further includes a height detector that is provided in such a manner as to face a front end face of the main-body housing part, interposing the skid between the height detector and the front end face and that detects a height of an object in a direction parallel with a measurement axis. When the height detector detects the object at the same height of the height of the main-body support foot in the measurement axis direction, the drive unit automatically starts driving in order for the stylus unit to perform scanning measurement of the surface of the workpiece.