Friction stir spot welding was put to practical use as a direct joining process of aluminum in 2003, and well-established as joining method of panel materials such as engine hood and door made of aluminum alloy thin sheet. On the other hand, application of aluminum to body frame has started in recent years, and needs of direct joining of such as thicker wrought aluminum and die-casting material have increased. To clarify applicability to body frame of friction stir spot welding, influence of process parameter on tensile shear strength was examined with use of aluminum die-casting and aluminum sheet. As a result, tensile shear strength that surpass JIS A-class of aluminum resistance spot welding can be obtained in combination of materials including die-casting. And it has been understood that there is possibility to be able to apply to body frame in friction stir spot welding.