A slim vapor chamber includes a first plate, a second plate and a capillary structure. The periphery of the second plate is connected with that of the first plate to form a chamber. The capillary structure is disposed on an inner wall of the chamber. Both of a side of the first plate facing the second plate and a side of the second plate facing the first plate are formed with a plurality of supporting structures, which include a plurality of supporting pillars and a plurality of supporting plates, by an etching process.