The present disclosure relates to a surface roughness sensor apparatus. The surface roughness sensor apparatus includes: a rotatable rotation shaft; a piezoelectric sensor provided along a circumference of the rotation shaft, rotated by rotation of the rotation shaft, and configured to generate a sensing signal in response to a pressure applied by a surface of an object as being in direct contact with the surface of the object; and a signal transfer unit configured to transfer the sensing signal generated and transmitted by the piezoelectric sensor to the outside of the sensor apparatus, and the piezoelectric sensor may be rotated in a direction in which a relative movement between the piezoelectric sensor and the surface of the object is made at a contact point with the object to minimize damage to the surface of the object.