In this study, bending test was conducted as beam members in timber roadside safety barrier. The flexural properties of pitch pine round timber according to the diameters were evaluated. And then grading based on the growth characteristics applied to choosing the pitch pine round timbers which is met the criteria of guideline (Japan, 2008). MOR of round timber 160 mm is higher than other specimens from 100 mm to 140 mm. Because of lower juvenile wood ratio and higher density. The MOE of round timber is decreased according to the increment of diameter. Only 32% of the specimens has passed the limitations. Performance of pitch pine round timbers has confirmed to suitability roadside safety beam members according to the guideline (Japan, 2008).