As an antitumor drug which is excellent in terms of antitumor effect and safety, there is provided an antibody-drug conjugate in which an antitumor compound represented by the following formula is conjugated to an antibody via a linker having a structure represented by the following formula: -L 1 -L 2 -L P -NH-(CH 2 )n 1 -L a -L b -L c -wherein the antibody is connected to the terminal of L 1 , and the antitumor compound is connected to the terminal of L c with the nitrogen atom of the amino group at position 1 as a connecting position.本發明係提供一種抗體-藥物複合體,作為為抗腫瘤效果與安全性面優異的抗腫瘤藥,其特徵為透過下式:-L1-L2-LP-NH-(CH2)n1-La-Lb-Lc-所示的構造之連結物,使下式所示的抗腫瘤性化合物與抗體結合(抗體係於L1之末端結合,抗腫瘤性化合物係以第1位之胺基之氮原子作為結合部位,於Lc之末端結合)。
