The present invention relates to a spreading device and a prepreg producing system including the same. A moving roller and fixing rollers in left and right thereof are horizontally formed, and the moving roller has a structure in which a cross-sectional surface becomes larger towards the center. The moving roller reciprocates in the longitudinal direction of the moving roller by means of a moving means. Through reciprocation of the moving roller having a convex center, a raw yarn can be rapidly and easily opened. The spreading device comprises: a material supply unit for disposing a roller having a raw yarn wound thereon on a creel rod, and releasing and supplying the raw yarn; a destarching device for removing a starching agent of the raw yarn by passing the raw yarn through an electric furnace; a spreading device previously formed; an additional material supply unit having a roller wounded with a thermal denaturing resin sheet and a roller wounded with a release sheet, releasing materials wound on each of the rollers, having thermal denaturing resin on both sides of the raw yarn, and supplying the material to make the release sheet disposed outside each thermal denaturing resin; a heating unit having multiple heating rollers disposed up and down, wherein materials pass through the heating rollers, so the thermal denaturing resin is laminated on the raw yarn; a hardening unit for cooling the thermal denaturing resin laminated on the raw yarn through the cooling unit having a cooling chamber for blowing air into a sealed space and multiple cooling rollers disposed up and down; a release sheet removing unit for removing the release sheet adhered on the raw yarn; and a winding device for winding a prepreg in which the thermal denaturing resin is laminated on the raw yarn. Accordingly, a prepreg including an obtained raw yarn can be rapidly and easily produced