A device for laying up a dry preform having an elongated shape includes a punch that reproduces the elongated shape of the dry preform, a depositing assembly, and a mobile carrier that moves at least one of the punch and the depositing assembly. The depositing assembly deposits, onto the punch, a fibrous band including a small amount of binding agent to make up the dry preform having a cross-section with at least two non-coplanar wings. The depositing assembly also includes pressing devices that press the fibrous band, a channel that pre-shapes the fibrous band to have the cross-section, and a calibration device that applies a normal pressure to all surfaces of the dry preform that are opposite from the punch while cooling the pressed portion of the fibrous band to control a thickness of the dry preform having the cross-section.