Disclosed is a glass fiber-reinforced composite material, an asphalt mixture using the same, and a manufacturing method thereof, the method comprising manufacturing, as a mixed structure, a bundle type fiber reinforcing material by coating with a polypropylene resin; a scrap reinforcing material having pellet or particle shaped glass fiber scrap, the glass fiber scrap having economical and outstanding physical properties and several strands of glass fiber; and adding the same to a hot-mix asphalt mixture, thereby capable of being injected at a plant construction site in a simple manner and improving the performance of the asphalt by preventing the phenomenon of the fiber becoming entangled within the produced hot asphalt mixture.