Provided is an anti-CD10 antibody which exhibits excellent effects in treating malignant tumors. An anti-CD10 antibody having the same amino acid sequence as the heavy chain CDR1 to 3 and the light chain CDR1 to 3 of the antibody produced by the hybridoma of Accession No. NITE BP-02489 is used.悪性腫瘍の治療に優れた効果を示す抗CD10抗体を提供する。受託番号NITE BP-02489のハイブリドーマにより産生される抗体の重鎖CDR1~3及び軽鎖CDR1~3のアミノ酸配列と同一のアミノ酸配列を有する、抗CD10抗体を用いる。