Abstract: A vertical mill for material such as cement raw materials, clinker, coal, or the like comprises a grinder portion which has rollers arranged to grind the material by their rolling on a rotary table, a separator means which is positioned above the grinder portion and which classifies the ground material conveyed pneumatically from the grinder portion to the separator means by the two opposite forces of centrifugal force of a rotary disk and of fluid resistance of a vortex flow, a plurality of straightening vanes which are mounted between the casing and the inner cone and which adequately regulate the direction of the fluid in the lower portion and in the upper portion in passage between the grinding portion and the separator means, and a casing outside the separator means having the appropriate shape for forming a horizontal vortex flow in the separator means. The aforesaid vertical mill structure improves the classifying efficiency of the separator means.