An input/output device is provided. The input/output device may include an output device having a display surface, on which characters or symbols are displayed, a body rotatably provided above the display surface, a body through-hole formed in the body to allow the display surface to be visible from an outside of the body, a signal generation device configured to generate a control signal according to whether the body is rotated, and a controller configured to control the output device based on the control signal input from the signal generation device.