Abstract: [OBJECT] To clearly awaken a pedestrian who crosses in front of an automobile to the fact that an automobile driver is depressing a brake pedal. [ACHIEVING MEANS] The invention is a display device of operation state of automobile brake that includes a brake operation detection switch (Bp) and a light emitting device (2). The brake operation detection switch (Bp) is actuated by depressing a brake pedal (3) and outputs a brake actuating signal to the light emitting device (2). The light emitting device (2) is disposed on an undersurface of a front of an automobile body (1), and emits diffused light in a fixed range of the front of the automobile body by receiving an input of the brake actuating signal so that the diffused light forms an optical projection image (Pi) on a road within a range of a shadow of the automobile body (1) as a caution arousing sign.