The paper deals with issues and shows the relevance related to the use of composite milling heads for machining wide flat surfaces. A 3D model of a composite milling head is presented. Shown, the design of the composite milling head with four face mills allows the milling of planes in mutually perpendicular directions. The surface machined with a single pass milling is continuous in width. It allows to shorten the cutting length and machining time, increasing productivity wide flat surfaces by milling.