To investigate the solid state weldability on SUS316L alloy, this work was carried out. Friction welding as a solid state welding was introduced and conducted at a rotation speed of 2,000 rpm and a friction pressure of 25 MPa on tube typed specimens. After this work, the grain boundary characteristic distributions such a grain size, shape and misorientation angle of the welds were clarified by electron backscattering diffraction method. The application of friction welding on SUS316L resulted in a significant refinement of the grain size in the weld zone (6.03 μm) compared to that of the base material (57.55 μm). Despite the grain refinement, the mechanical properties of the welds indicate relatively low or similar to the base material. These mechanical properties are due to dislocation density in the initial material and grain refinement in the welds.