The present disclosure provides an apparatus for manufacturing a silicon substrate for solar cells using continuous casting, and a method for manufacturing a silicon substrate using the same. The apparatus includes a raw silicon feeder, a silicon melting unit melting raw silicon to form molten silicon, a molten silicon storage unit storing the molten silicon supplied from the silicon melting unit and tapping the molten silicon to provide a silicon melt having a constant thickness, a transfer board transferring the tapped silicon melt, and a silicon substrate forming unit cooling the silicon melt transferred by the transfer board to form a silicon substrate. The molten silicon stored in the molten silicon storage unit has a surface temperature of 1300˜1500° C., the transfer board is preheated to 700˜1400° C., and a transfer time of the silicon substrate after tapping the molten silicon from the molten silicon storage unit is 0.5˜3.5 seconds.