Regardless of age difference gender difference individual difference treatment history, in upper layer of the skin, especially in the dermis layerSelectively injecting a medical solution to a relatively shallow portion close to the epidermis layer of the skin from the skin surfaceIt does not leak, it forms a wheal, and even if it is extremely small amount it can acquire the immunogenic potential etc.It is an object of the present invention to provide an injection needle assembly. The injection needle assembly (10) has a needle communicating with the needle proximal end (23) from the needle point (21)A note consisting of a needle tube provided with a hole (24) and having a blade face (22) at the needle tip (21)A needle (20), a distal end portion (31 c) and a proximal end portion, and a distal end portionAnd a needle hub (30) for holding the injection needle (20), and the needle hub (30) is provided with a needleA front end face (31 b), and the probe tip (21) projects from the probe tip side end face (31 b)The injection needle (20) has an outer diameter ( 1) of 0.15 mm or more and 0.The length from the end face on the needle tip side (31 b) to the tip of the needle (21) is less than 20 mm,The needle length (L1) is set to 0.50 mm or more and 1.25 mm or less, the tip end side face (31 b) to the blade surface (22) is set to 0.10 mm or more.It shall be 70 mm or less.年齢差・男女差・個人差・治療歴に関わらず、皮膚上層部、特に真皮層中の表皮層寄りの比較的浅い部位へ選択的に、薬液を注入して、皮膚表面から遺漏せず、膨疹を形成させ、極少量であっても免疫惹起能などを獲得させ得る注射針組立体の提供を目的とする。 注射針組立体（１０）は、針先（２１）から針基端（２３）に連通する針穴（２４）が設けられ針先（２１）に刃面（２２）を有する針管からなる注射針（２０）と、先端部（３１ｃ）と基端部とを有し、先端部（３１ｃ）に注射針（２０）を保持する針ハブ（３０）とからなり、針ハブ（３０）は針先側端面（３１ｂ）を有し、針先（２１）は針先側端面（３１ｂ）から突出するものであって、注射針（２０）が、外径（φ１）を０．１５ｍｍ以上０．２０ｍｍ未満とし、針先側端面（３１ｂ）から針先（２１）に到るまでの突出針長（Ｌ１）を０．５０ｍｍ以上１．２５ｍｍ以下とし、針先側端面（３１ｂ）から刃面（２２）に到るまでの針胴長（Ｌ２）を０．１０ｍｍ以上０．７０ｍｍ以下とする。
