[Problem to be solved] The present invention provides an antibody-drug conjugate (ADC). The present invention also provides a conjugate of an anti-CD71 antibody or an antigen-binding fragment thereof with a drug. The present invention further provides a conjugate of Fab′； with a drug. The present invention further provides a composition comprising the conjugate for delivering the drug to a tissue or a cell of muscle or the like.[Solution] A conjugate of an anti-CD71 antibody or an antigen-binding fragment thereof with a drug, and a conjugate of Fab′； of an antibody with a drug.
