To provide a friction stirring and joining spot welding method capable of effectively suppressing or preventing occurrence of burrs on a surface of a metal member to be welded which is pressed against a rotary tool when performing the friction stirring and joining point welding of the overlapped metal member by using a double action type rotary tool.

A backing tool 4 is arranged on a back side of a lower metal plate 2b out of overlapped metal plates 2a, 2b by using a double action type rotary tool 10 consisting of a cylindrical shoulder member 12 and a rod-shaped probe 14, a burr holding jig 6 is moved in the transverse direction with respect to the rotary tool 10, and these jigs are integrally clamped on the upper metal plate 2a by a clamp 8. The rotary tool 10 is inserted through an operation hole 20 formed in the burr holding jig 6, and the friction stirring and joining point welding of the metal plates 2a, 2b is performed thereby.