The chemical liquid parts having the desired skin can be effectively implanted to provide a transdermal administration device that can reduce the amount of liquid medicine. It is a chemical liquid injection needle 1 which is attached to the tip of the syringe 6. Chemical liquid injection needle 1, the body 10 of the chemical liquid injection needle, and a plurality of needle 11 which protrudes from the front end surface of the chemical injection needle body 10, the tip of the needle 11 is at an angle relative to the longitudinal direction of the needle 11 discharge port 13 of the chemical liquid is formed and is cut at the tip of the needle 11, a plurality of needles 11 are arranged at equal intervals on the virtual perfect circle on the circumference of the distal end surface of the liquid injection needle body 10, the needle 11 the direction of the discharge opening 13 of, and substantially center of the radial or substantially above circularity, toward the center of the perfect circle facing opposite directions.皮膚の所望とする箇所に薬液を効果的に注入でき、薬液の使用量を低減できる経皮投薬装置を提供する。注射器6の先端部に取り付けられる薬液注入針1である。薬液注入針1は、薬液注入針の本体10と、薬液注入針本体10の先端表面より突出する複数本の針11とを有し、針11の先端が針11の長手方向に対して斜めに切断されて針11の先端に薬液の吐出口13が形成され、複数本の針11は、薬液注入針本体10の先端表面の仮想の真円の円周上に等間隔で配置され、各針11の吐出口13の向きが、実質的に上記真円の中心に向かう半径方向、もしくは実質的に上記真円の中心方向とは反対方向を向いている。
