A glass-melting device for producing glass fibers capable effectively reducing inclusion of bubbles into glass fibers to be spun, and a method for producing glass fibers using the same are provided.A glass-melting device 100 for producing glass fibers comprises: a first glass-melting tank 12; a conduit 14 extending downward from the first glass-melting tank 12; a sucking device 18 for exposing the first glass-melting tank 12 to a reduced-pressure atmosphere; a second glass-melting tank 20 provided on a lower portion of the conduit 14 and exposed to an atmospheric-pressure atmosphere; and a bushing 22 provided at a bottom portion of the second glass-melting tank 20 and equipped with a number of nozzles 22a.