The multifractal analysis (MFA) of the spatial microform area formed on the surface of steel C35 and aluminum alloy AA2024 at the face milling was implemented. The input information for the MFA was micro-images of the machined workpiece surface. Multifractal (MF) spectra and their main parameters are calculated for the surface of samples machined at various cutting conditions. Renyi’s numbers and fractal ordering parameters were chosen as the most informative MF parameters describing the surface structure. It is shown that the MF functions of the system correspond to their canonical forms. Quantitative relationships between the parameters of MF spectra for the surface area of microforms formed during machining surfaces of steel and aluminum alloy workpieces and the cutting conditions were obtained. The physical processes that are responsible for the formation of the observed MF spectra on the surface of the workpieces depending on feed and depth of cut at the face milling were discussed. The developed computational technique can be used to describe and analyze the state of spatial fractal structures formed on the surface of other materials.