A waterproof keyboard comprises: keys, an elastic rubber layer, a circuit board layer, a bottom board, and a sealing layer. The keys are mounted on the bottom board on which a plurality of apertures are disposed, and the sealing layer is disposed under the bottom surface of the bottom board. Corresponding to the apertures on the bottom board, respective adhesives are formed on the sealing layer so as to firmly adhere the sealing layer to the bottom surface of the bottom board.