To provide an apparatus for producing polycrystalline silicon and a method therefor to allow improvement in efficiency of polycrystalline silicon production by minimizing reactor downtime and to allow polycrystalline silicon production at a relatively low cost and in a large amount in a zinc reduction process for recovering formed silicon in a solid state. In a silicon producing apparatus for producing polycrystalline silicon by reducing silicon tetrachloride with zinc, vertical reactor 1 has reactor upper body 2 and reactor lower body 3 that can be vertically detached, and reactor lower body 3 is movable in up-and-down and left-right directions.