A continuous preform device for a composite stringer continuously preforms the composite stringer having three-dimensional curved surfaces in an efficient manner, the continuous preform device including a dispenser device 200 adapted to supply a prepreg laminate to a next process by sandwiching upper and lower faces of the prepreg laminate with carrier films, a section preform device 300 adapted to form the prepreg laminate sandwiched between the carrier films into a desired cross-sectional shape during passage, a press/puller device 400 adapted to apply a pressing process to the prepreg laminate and intermittently feed a composite downstream, and a curing mold forming device 500 adapted to preform the prepreg laminate into a desired stringer shape on a curing mold 20, which are placed in a straight line from upstream to downstream.