There is described an operation panel, which is detachably or movably mounted onto an image-forming apparatus, and which includes a data-inputting section to input operational data necessary for operating the image-forming apparatus and/or a displaying section to display status information of the image-forming apparatus. The operation panel comprises: a circuit board, on which electronic parts are mounted; a supporting member to support the circuit board, the data-inputting section and/or the displaying section, so as to integrate them into a single unit serving as the operation panel; a signal line, through which electronic signals are communicated between the operation panel and the image-forming section; and a conductive member for directly grounding at least one of the data-inputting section, the displaying section and the circuit board to a conductive main-frame of the image-forming apparatus. The signal line and the conductive member are disposed at separate positions being different relative to each other.