A chromatic confocal scanning apparatus comprises a light source for producing light rays comprising a plurality of wavelengths, a first screen having an open elongated slit which allows a strip of light rays produced from the light source to pass through the slit and a cylindrical objective lens both to converge the light rays onto an object surface that is to be measured, and to image light rays reflected from the object surface. An intermediate cylindrical lens set converges a strip of light rays imaged from the cylindrical objective lens to pass through an open elongated slit comprised in a second screen, and a color sensor receives light rays which have passed through the slit of the second screen for determining a plurality of wavelengths of the said strip of light rays, to thereby construct a height profile of at least a portion of the object surface.