The present invention is directed to provide infection inhibitor products for an influenza virus. More specifically, an inhibitory substance that inhibits the activity of an RR sequence to permit a molecule of which it forms a part to be introduced into cells, such as an antibody that recognizes a peptide having an amino acid sequence RERRRKKR (SEQ ID NO. 1), is formulated as a pharmaceutical composition and an infection inhibitor products for an influenza virus containing the pharmaceutical composition is manufactured.