The purpose of this research was to investigate the effects of main factors on the surface roughnessin milling process of Palmyra Palm wood face by computer numerical controlled milling machine and usingshell end mill cutting tools 6 edges. The main factors including speed, feed rate, depth of cut and angle of cutwere investigated for the optimum surface roughness. Generally, acceptable surface roughness was between3.0-9.0 μm before sanding process. In the experiment, Palmyra Palm wood of 11-13% humidity was used at800-1200 rpm in cutting speed and feed rate at 0.03-0.05 mm/tooth. The result of preliminary trial showedthat the depth of cut and the angle of the cut had no effect on surface roughness. It was found from theexperiment that the factors affecting surface roughness were feed and speed, with tendency for reduction ofroughness value at a lower feed rate and greater cutting speed. Therefore, in the facing process for PalmyraPalm wood it was possible to determine a face milling condition by means of the equation Ra=0.954+20.4feed+0.00126 speed. This equation was employed at a limited speed of 800-1200 rpm, and the feed rate of0.03-0.05 mm/tooth. The result from the experiment of the mean absolute percentage error of the equationof surface roughness is 6.10% which is less than the margin of error, and is acceptable. Keywords: Design of Experiment; Computer Numerical Controlled Milling Machine; Palmyra PalmWood; Surface Roughness