The present disclosure provides an apparatus for manufacturing a single crystal silicon ingot having a dual crucible for silicon melting which can be reused due to a dual crucible structure. The apparatus includes a dual crucible for silicon melting, into which raw silicon is charged, a crucible heater heating the dual crucible to melt the raw silicon into molten silicon, a crucible drive unit controlling rotation and elevation of the dual crucible, and a pull-up drive unit disposed above the dual crucible and pulling up a seed crystal dipped in the molten silicon to produce a silicon ingot. The dual crucible has a container shape open at an upper side thereof, and includes a graphite crucible having an inclined surface connecting an inner bottom and an inner wall, and a quartz crucible inserted into the graphite crucible and receiving the raw silicon charged into the dual crucible.