A suction device includes a baseplate, a mounting board, and at least one suction assembly. The mounting board is spaced from the baseplate. The at least one suction assembly includes two bearings and a pole. The two bearings are secured on the baseplate and the mounting board, respectively. The pole is a hollow structure and passes through the two bearings. A suction head and a connection assembly are coupled to two opposite ends of the pole. The connection assembly connects to a vacuum pump to generate a vacuum in the suction head.