Metastasis is a key aspect of tumor malignancy, and several malignant tumors show expression of various mature N-type glycans. In particular, beta1-6 branching N-acetylglucosamine (GlcNAc) is abundantly expressed as a part of high-mannose glycans in various highly metastatic cancers. Phaseolus vulgaris agglutinin-L(4) isolectin (L(4)-PHA), which adheres to beta1-6 GlcNAc specifically, has been used for in situ cancer diagnosis. Bionanocapsules (BNCs), hollow particles with a diameter of approximately 80 nm and composed of hepatitis B surface antigen (HBsAg) and a lipid bilayer, have been developed as human liver-specific nanocapsules for in vivo drug delivery system. In this study, we have generated L(4)-PHA-displaying BNCs (PHA-BNCs) and examined whether L(4)-PHA could retarget the BNCs to malignant tumors as a "biosensor" distinguishing tumor metastaticity. Fluorescence-labeled PHA-BNCs injected systemically into a mouse xenograft model were found to accumulate in beta1-6 GlcNAc-expressing malignant tumors. The PHA-BNCs were able to deliver DNA to the malignant cancer cells. These results open up the possibility of using L(4)-PHA lectin as a targeting molecule in a drug delivery system, and of using PHA-BNCs as a novel nanodevice for malignant tumor-specific bioimaging and drug delivery.