Basalt filament is manufactured such that the fiber diameter can be controlled and the filament is not severed during winding. A network former and a glass modifier are formed and maintained with respect to basalt rock ore, and the crystallization and binding of basalt fiber are inhibited, the heat-resistance property of basalt fiber is greatly improved from the conventional 750° C. to 850 or 900° C., and significant cost reduction is achieved over conventional products. The method includes: grinding basalt rock as a material; washing a resultant ground rock; melting the ground rock that has been washed; transforming a molten product into fiber; and drawing the fiber in an aligned manner, and winding it. The temperature of the molten product in the melting step is 1400 to 1650° C., and log η is 2.15 to 2.35 dPa·s and preferably 2.2 to 2.3 dPa·s, where η is the viscosity of the molten product.