In order to reduce congestion of attachments between an aircraft engine and its attachments, an engine assembly is provided, the primary structure of the device of which includes a structural cover surrounding the engine and connected on a central box, the cover including an outer skin interiorly delimiting a secondary flow. A group of main mounts is provided as a group of secondary mounts laid out at the rear of the group of main mounts, the group of main mounts including a plurality of bolts distributed around the longitudinal axis of the engine and ensuring the attachment of a front end of the cover to the hub of the intermediate case, and a group of secondary mounts including a plurality of secondary mounts distributed around the axis and ensuring attachment of a rear portion of the engine to a rear end of the cover.