An apparatus for manufacturing polysilicon using a chemical vapor deposition (CVD) reactor is provided. The apparatus for manufacturing polysilicon includes: a reaction chamber including a substrate and a reactor cover; at least a pair of electrodes installed through the substrate by an insulating member and connected with a power supply; at least a pair of filaments which are coupled with the pair of electrodes by an electrode chuck and of which upper ends are connected to each other; and a cover assembly including an electrode cover surrounding an upper surface and a side of each of the pair of electrodes on the substrate and a cover shield covering the upper surface of the electrode cover.