The invention concerns an injecting/blowing device comprising at least one mold for injecting a thin-walled hollow preform capable of being transformed into a more voluminous hollow body by blowing, said mold including a counter mold defining the inner surface of the cavity, a core located in the cavity and spaced apart from said inner surface, a preform impression located between the counter mold inner surface and the core, and which will receive the melt, at least two main preferential flow channels (CEP) optionally at least two secondary preferential flow channels (CEP), each CEP being delimited by at least one recessed zone at the surface of the core and the inner surface of the cavity. Said device is characterized in that: the main CEP are located only at the impression zone corresponding to the zone for transforming the preform; and in that the optional secondary CEP are discontinuous, distinct from the main CEP, and located at the impression zone corresponding to the base and/or the body and/or the ring of the preform.