To eliminate possibility of forming a loop at a continuous yarn (3) to be supplied to a cutting unit (12) at an end of a mold filling operation even if a drawing speed of the yarn (3) is relatively high in the case of manufacturing a molding of a plastic reinforced by a long fiber (20) and to obviate a breakage of the yarn (3) until next restart of the mold filling operation.

An apparatus for manufacturing the molding of the long fiber- reinforced plastic comprises an inlet (23) of the air for applying a tension allocated to a guide (5) of the continuous yarn (3) to maintain the yarn (3) in a state in which the tension is applied to the yarn (3) by the air in a direction opposite to a conveying direction.