Tensile test of full-size lumber with square and round section, used as column and beam, has never been conducted because of the difficulty of loading. This study aimed to develop full-size tensile testing method of structural lumber and to evaluate several mechanical properties of lumber. Specially designed fixing jig, transmitting sufficient axial force to lumber, was developed. Although many knots were observed at the surface of specimens, the maximum tensile stress is much higher than the standard material stress of normal grade material by AIJ code. As the results, knot was found not to be defect for tensile loading.