The invention discloses a three-high mill, which comprises an outer frame which is arranged along a rolling axle L, a plurality of rolling machine cores which are arranged inside the outer frame, an driving device which is enabled to actuate rolls to rotate along each rolling axle, and a roll adjusting device. Three radial guiding slots which are distributed evenly along a periphery of a machine core are opened on each rolling machine core, and the roll adjusting device is connected with a bearing seat which is in a radial guiding slot through a sliding seat of a roll. The roll slides along the radial guiding slot through the roll adjusting device, the independent radial adjustments of the roller can be realized, distances between rotary central lines (A1, A2, A3) of rollers and a rolling axis (L) can be adjusted, and the invention guarantees that hole type central lines of the roll can be always on primitive moving radius directions during a course of roll movements. The speeds of hole-type points which are in symmetry with two sides of a roller center of a mill are equal, and geometric figures, degree of accuracy and surface smoothness of rolled metals can be increased.