To provide an anti-EphA4 antibody or an EphA4-binding fragment thereof that is capable of binding to EphA4 and inhibiting the binding of EphA4 and the ligands thereof, and a pharmaceutical composition containing these as an active ingredient. A mouse anti-EphA4 antibody having binding affinity for EphA4 was acquired, and the sequence of the complementarity-determining region (CDR) of the mouse anti-EphA4 antibody was identified. This made it possible to produce a humanized antibody including the CDR sequence of the mouse anti-EphA4 antibody in the variable regions of the heavy and light chains.本發明提供一種能夠與EphA4結合，而抑制EphA4與其配位基的結合的抗EphA4抗體或其EphA4結合片段及含有該等作為有效成分的醫藥組合物。取得對EphA4具有結合親和性的小鼠抗EphA4抗體，並特定出該小鼠抗EphA4抗體的互補決定區(CDR)的序列。由此，能夠製作在重鏈及輕鏈的可變區含有所述小鼠抗EphA4抗體的CDR序列的人源化抗體。
