A printhead a supplying portion with a supplying opening of a filament; a melting portion to melt a filament supplied; a discharging portion having a discharging opening to discharge the melted filament. A heat insulating portion between the supplying portion and the melting portion are integrally formed to effectively suppress heat in the melting portion conducting to the supplying portion even when the melting portion is heated to high temperature, to maintain the temperature of the supplying portion to an appropriate temperature, and to efficiently utilize heat by the melting portion as a result of heating the melting portion.