A plate bending machine for bending a plate clamped between a lower die and a pressure die by a blade of a bending die mounted on a bend beam which is controlled in the vertical and horizontal directions. The bend beam has a vertical cross-section of substantially C-shaped configuration, and includes a first bending die attached to an upper portion of the substantially C-shaped configuration and a second bending die attached to a lower portion of the same. Blades are formed on at least one of the first and second bending dies to extend in the upward and downward directions, respectively. The horizontal bend arm may be connected to one end of a vertical bend arm which is disposed substantially vertically, by a shaft B (eccentric shaft).