A core manufacturing apparatus using an inorganic binder includes a mulling sand feeder that supplies mulling sand comprising sand and the inorganic binder, a mold that receives the mulling sand from the mulling sand feeder and molds the mulling sand into a core, and a mold heating device that heats the mold. The mold includes an upper mold and a lower mold and has a plurality of cavities formed therein in which the mulling sand is deposited. The mold further includes an inner fluid channel through which fluid flows.