The present invention provides a fusion protein of BDNF and an anti-human transferrin receptor antibody, wherein in a heavy-chain variable region of said antibody, (a) CDR1 includes an amino acid sequence of SEQ ID NO:66 or SEQ ID NO:67, (b) CDR2 includes an amino acid sequence of SEQ ID NO:13 or SEQ ID NO:14, and (c) CDR3 includes an amino acid sequence of SEQ ID NO:15 or SEQ ID NO:16.