This research aims to propose the method and equipment to preliminary-announce and indicate the surrounding people both the speed of motion and the direction of motion of the mobile robot that moves on a two-dimensional plane. This paper discusses the mobile robot PMR-6, in which the liquid crystal display (LCD) is set up on the mobile unit, and the state of operation at 1.5 s before the actual motion is indicated. The basis of the content to display is 'arrow' considering the intelligibility for people even at first sight. The speed of motion is expressed as the size (length and width) of the arrow and its color based on traffic signal. The direction of motion is described with the curved condition of the arrow. The characters of STOP are displayed in red in case of stop. The robot was exhibited to the 2005 International Robot Exhibition held in Tokyo. About 200 visitors answered to the questionnaires. The average of five-stage evaluation is 3.56 and 3.97 points on the speed and on the direction respectively, so the method and expression were evaluated comparatively intelligible. As for the gender, the females appreciated about the speed of motion than the males on the whole. Concerning the age, some of the younger age and the upper age admired highly about the direction of motion than the middle age.