The present invention provides a technology in production of a prepreg and enhances the production efficiency, in which the technology allows the arrangement property and rectilinearity of reinforcing fibers to be well maintained and allows any resin to be applied stably at a high speed. A prepreg is produced by a method which includes: discharging a molten resin in planar form to form a resin film, and applying the resin film onto a reinforcing fiber sheet conveyed continuously, wherein the reinforcing fiber sheet is conveyed substantially in the horizontal direction, and wherein an angle made between the discharge direction of the resin and the conveyance direction of the reinforcing fiber sheet 1a is 80° or less.