Aramid fiber reinforced rubber (AFRR) is a new composite material developed for transmission belt. Transmissibility of belt is considerably dominated by frictional characteristics of belt surface contacting with pulley. Transmissibility of belt just like as V-ribbed belt made of AFRR, which is finished by grinding, is influenced by grinding conditions as well as its material. In this paper, by investigating the surface generation process in grinding AFRR with diamond wheel, a grinding technique for a required transmissibility which is represented by coefficient of friction on ground surface of AFRR, is made clear. Main conclusions in this paper are as follows : (1) The coefficient of friction on ground surface of AFRR, which is determined by a projecting length of aramid fiber from matrix surface, increases as the projecting fiber length decreases. (2) In the steady grinding state, a required projecting fiber length of AFRR is given by controlling grinding conditions with grinding force ratio. (3) There exist the matrix removal region for lower initial length of projecting fiber or the fiber removal region for higher one, than cutting depth of grinding wheel, and therefore both projecting fiber length and matrix size can be adjusted by either grinding of the two regions.