A coupling device is configured to, using a coupling member, couple a first plate made of a first metal and a second plate made of a second metal to each other, and includes a first electrode, a second electrode, a power source, a driver, and a controller. The power source is connected to the first electrode and the second electrode. The driver is configured to move the first electrode and the second electrode relative to the coupling member, the first plate, and the second plate. The controller is configured to control the power source and the driver to electrify the coupling member, the first plate, and the second plate while controlling the first electrode and the second electrode to apply pressure to the coupling member, the first plate, and the second plate.