PROBLEM TO BE SOLVED: To provide an antibody that binds to human HER3, a pharmaceutical composition comprising the antibody, and uses thereof.SOLUTION: Provided is an antibody that binds to human HER3, which antibody comprises a heavy chain variable domain VH and a light chain variable region VL, where the heavy chain variable domain VH comprises a CDR3H region, a CDR2H region and a CDR1H region of a heavy chain variable domain VH, each having a specified amino acid sequence respectively, and the light chain variable domain VL comprises a CDR3L region, a CDR2L region and a CDR1L region of a light chain variable domain VL, each having a specified amino acid sequence respectively. Also provided are pharmaceutical compositions comprising the antibodies and use of the antibodies in production of medicines for cancer treatment.【課題】ヒトHER3に結合する抗体(抗HER3抗体)、該抗体を含有する薬学的組成物、及びそれらの使用の提供。【解決手段】重鎖可変ドメインが、特定のアミノ酸配列の重鎖可変ドメインVHの、CDR3H領域、CDR2H領域、及びCDR1H領域を含み、他の特定のアミノ酸配列の軽鎖可変ドメインVLの、CDR3L領域、CDR2L領域、及びCDR1L領域を含む、ヒトHER3に結合する抗体、該抗体を含有する薬学的組成物、及びがんの治療のための医薬の製造における該抗体の使用。【選択図】なし