Solid-phase resistance spot joining apparatus

A solid-phase resistance spot joining apparatus comprising:

• a pressurization shaft that presses a plurality of overlaid objects from an axial direction in a plastically deformable manner;
• an electrode arranged around the pressurization shaft, the electrode applying a voltage to the plurality of objects;
• and
• a drive mechanism capable of moving the electrode relatively to the pressurization shaft in the axial direction, wherein
• the drive mechanism includes
• a cylinder fixed to the pressurization shaft to surround the pressurization shaft, the cylinder being provided with an inner circumferential surface that extends along the axial direction, and
• a piston accommodated in the cylinder while the piston is connected to the electrode, the piston being driven by a pressure of fluid,
• the piston partitions an internal space in the cylinder into a first chamber and a second chamber, and
• as the fluid alternately goes in and out of the first chamber and the second chamber, the piston is driven in the axial direction while the piston slides with respect to the inner circumferential surface, and the electrode is movable in the axial direction together with the piston.