A friction stir spot welding apparatus includes a pin member, a shoulder member, a rotation driver, a forward/backward movement driver, and a controller. The controller controls the forward/backward movement driver, such that the pin member and/or the shoulder member press workpieces before a clamp member presses the workpieces, and then controls the rotation driver and the forward/backward movement driver, such that the pin member and the shoulder member stir the workpieces.