Provided is a control device of grain preparation equipment, and the device can master operation conditions at a glance. The device can rapidly master falut causes when faults occur. A touch panel control portion that the control device of grain preparation equipment has has a production line process display function, an error display function, and an abnormity history display function. Normal operation condition is displayed through illumination when grain preparation equipment is normally driven. When the grain preparation equipment has faults, the error display function illuminates to display where the falut position is, and display a restoration sequence of the fault. The abnormity history display function displays past history of faults when the grain preparation equipment has faults.