A spot welding apparatus which performs spot welding of a plurality of plate materials which are lapped to each other, comprises a displacement driving unit which displaces lapped portions of the plurality of plate materials and a tool relatively to each other; a rotation driving unit which rotates the tool; and a controller which controls the displacement driving unit and the rotation driving unit so that the tool is plunged into the lapped portions in a state in which the tool is rotated to perform friction stir spot welding. The controller controls the displacement driving unit so that at least one friction stir spot weld is formed in a region of the lapped portions which is between a plurality of resistance spot welds formed by resistance spot welding.