A method for manufacturing hollow composite material turbomachine part, includes producing a fibrous blank in one piece by three-dimensional weaving of yarns, the blank including at least one de-bonded zone forming an internal cavity, inserting a shaping part into the internal cavity of the fibrous blank in order to obtain a preform, densification of the preform by a matrix in order to obtain a structure having a fibrous reinforcement consisting of the preform densified by the matrix, wherein the shaping part is flexible and wherein the shaping part is mechanically withdrawn from the structure after the densification.