The invention relates to an apparatus for deposition of polycrystalline silicon, including a reactor chamber with a reactor wall, at least 20 filament rods and gas inlet orifices for reaction gas in the reactor chamber, wherein each filament rod—except for the filament rods close to the reactor wall—has, at a distance of 150 to 450 mm, three further adjacent filament rods and one to three adjacent gas inlet orifices. The invention further relates to a process for depositing polycrystalline silicon on filament rods in such an apparatus, the gas inlet orifices are used to introduce a silicon-containing gas into the reactor chamber and the filament rods are heated to a temperature at which silicon is deposited thereon.