A suction disc is configured for abutting against a dressing covering over a wound. The suction disc includes a base plate and a case. The base plate has a first surface and a second surface opposite to each other. The first surface abuts against the dressing. The base plate has a first opening and a second opening. The first opening and the second opening respectively communicates with the first surface. The case has a first chamber and a second chamber. The case communicates with the second surface. The first chamber communicates with the first opening. The second chamber communicates with the second opening. The suction disc has a channel disposed inside a sidewall of the case surrounding the first chamber and penetrating through the base plate. An end of the channel communicates with the first chamber. Another end of the channel communicates with the first surface.