To provide techniques for efficiently incorporating, into muscle tissues, particularly muscle tissues consisting of skeletal muscle or myocardium, a drug to be functioned in muscular tissues, which is not incorporated into muscular tissues sufficiently when administered into a living body as it is.SOLUTION: Provided is a conjugate of anti-human transferrin receptor antibody and a drug, the drug having physiological activity for the drug to exert its function in muscle tissues, for example the drug being lysosomal enzymes such as acid α-glucosidase and α-galactosidase A.SELECTED DRAWING: Figure 1【課題】筋組織で機能させるべき薬剤であって，生体内に投与したときに，そのままでは筋組織へ十分に取り込まれない薬剤を，筋組織，特に骨格筋又は心筋により構成される筋組織に，効率よく取り込ませるための技術を提供すること。【解決手段】抗ヒトトランスフェリン受容体抗体と薬剤との結合体であって，該薬剤が筋組織で機能を発揮させるべき生理活性を有する薬剤，例えば，酸性α-グルコシダーゼ，α－ガラクトシダーゼＡ等のリソソーム酵素である，結合体。【選択図】図１
