The present invention provides a peptide having cell membrane penetrating activity, a transmembrane carrier comprising the peptide having cell membrane penetrating activity as an effective component, a transmembrane complex consisting of the peptide having cell membrane penetrating activity combined with a target substance, a transfection kit comprising the peptide having cell membrane penetrating activity and the target substance, use of the peptide having cell membrane penetrating activity for the manufacture of a transmembrane complex, use of the transmembrane complex for the manufacture of a medicament, and a method for delivering a target substance into cell interior which comprises administrating to a subject with a transmembrane complex consisting of the peptide having cell membrane penetrating activity combined with a target substance to induce transduction of the transmembrane complex into cell interior. The peptide having cell membrane penetrating activity of the present invention has a prominent penetrating efficiency as compared with the activities of prior TAT-derived peptides and so the peptide has applications on intracellular delivery in various research fields as well as on therapeutics of specific diseases where targeting of drugs is required at high efficiency. Accordingly, the peptide having cell membrane penetrating activity, the transmembrane complex consisting of the peptide combined with a target substance and the method for delivering a target substance into cell interior using the transmembrane complex of the present invention are very useful as drug delivery systems.
