Category for specialized measuring instruments that quantitatively measure product surface roughness. Measures surface roughness (Ra, Rz, Rmax, etc.) of machined parts and metal products using contact-type probes or non-contact laser systems for quality control and process management. Essential for surface quality evaluation after cutting, grinding, and polishing processes, used for surface finish inspection of automotive parts, precision mechanical components, and molds. Available in portable to stationary types with JIS standard-compliant measurement capabilities. Specialized equipment focused on measuring fine surface irregularity patterns, distinct from coordinate measuring machines and contour measuring instruments.