A flexible circuit board having enhanced bending durability and a method for preparing same are provided. The method comprises: forming a signal line and a first ground layer on a first dielectric body and forming a second ground layer on a bottom side of the first dielectric body; preparing a second dielectric body; preparing a first bonding sheet and a first protective sheet which is connected to one end of the first bonding sheet or of which one or more parts are overlapped on one end of the first bonding sheet; bonding the second dielectric body onto the first dielectric body by means of the first bonding sheet; forming a via hole such that the first ground layer and the second ground layer are conducted; and cutting in a width direction the second dielectric body placed on the first protective sheet.