A substrate attachment and detachment device appropriate for a double-sided holder is provided. The substrate attachment and detachment device is a device that holds a substrate in a substrate holder and/or releases the holding of the substrate using the substrate holder. The substrate holder includes a first frame and a second frame. The first frame and the second frame have openings, respectively. The device includes a substrate supporting unit that sandwiches the substrate between the first frame and the second frame. The substrate supporting unit includes a lower substrate supporter, and an upper substrate supporter. The lower substrate supporter is configured to come into contact with the substrate through the opening of the frame positioned on a lower side. The upper substrate supporter is configured to come into contact with the substrate through the opening of the frame positioned on an upper side.