To provide a closing operation alarm display unit for an opening and closing body, which can prevent the pinching of the human body or foreign matter by providing visual and concrete notification on danger in such a manner as to indicate which opening and closing body performs a closing operation, through the use of optical alarm display using light irradiation and light projection.

A laser emitting device 30 is arranged in a linear movement route. When a door sensor 20 detects a sliding door 10, a laser beam is applied (or projected) to the movement route, so that an alarm can be displayed in a prescribed display mode (for example, characters of "danger" written in a yellow color on a red ground are displayed in a blinking manner). When the sliding door 10 is moved to a closing position from an opening one by a door driving motor 11, a body ECU 100 issues a light emitting command to the laser emitting device 30 depending on the detection of the sliding door 10 by the door sensor 20, and makes the laser emitting device 30 perform the alarm display.