A method for manufacturing a ceramic core blank intended for the manufacture of hollow turbomachine blades using the technique of lost wax casting, the blank being manufactured by additive manufacture and comprising at least one first part intended to form the cavities of the hollow blades and at least one second part configured to allow the positioning of the core in a wax mold, the second part and the first part being positioned and held with respect to one another by means of a junction portion interposed between the first part and the second part, at least one through orifice extending through the second part, the junction portion and the first part, a first end of the through orifice opening to an outer face of the second part, and a second end of the through orifice opening to an outer face of the first part.