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.本發明係提供一種融合蛋白質,其係BDNF與抗人類運鐵蛋白受體抗體之融合蛋白質,並且該抗體係於重鏈之可變區中,(a)CDR1為包含序列編號66或序列編號67之胺基酸序列而成,(b)CDR2為包含序列編號13或序列編號14之胺基酸序列而成,且(c)CDR3為包含序列編號15或序列編號16之胺基酸序列而成者。