In a printer for corrugated cardboard sheets and a box making machine for corrugated cardboard sheets, a control device that controls an operation of an air cylinder is provided such that an ink supply roll is moved toward or away from a printing cylinder relative to an intermediate position of a gap between ends of a printing plate attached on a surface of a printing cylinder. With this configuration, ink of an ink supply roll is appropriately transferred to the printing plate, an ink film on the printing plate is uniformized, and then printing precision is enhanced.