Regardless of age difference, gender difference, or individual difference, selectively inject a drug solution such as a vaccine into the upper skin layer, especially near the epidermis layer in the dermis, so that it does not leak from the skin surface. The present invention provides a syringe for injecting a drug solution into the upper layer of the skin, which is capable of forming a bulge and obtaining or developing a medicinal effect such as sufficient immune-inducing ability even with a very small amount. The syringe 1 for injecting medicinal solution into the upper skin portion is provided with a needle hole 24 communicating from the needle tip 21 to the proximal end of the needle and having a blade surface 22 at the needle tip 21, a distal end portion 31c, and a proximal end portion. The needle hub 30 has a needle tip side end surface 31b, and the needle tip 21 protrudes from the needle tip side end surface 31b. Thus, the protruding needle length L1 of the needle tip 21 from the needle tip side end surface 31b is 1.15 mm ± 0.1 mm, and the blade surface length L2 of the blade surface 22 along the axis of the injection needle 20 is 0.60 mm ± It is set to 0.15 mm.年齢差・男女差・個体差に関わらず、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、ワクチンのような薬液を注入して、皮膚表面から遺漏せず、膨隆を形成させ、極少量であっても十分な免疫惹起能などの薬効を獲得させたり発現させたりすることができる、皮膚上層部への薬液注入用注射器を提供する。 皮膚上層部への薬液注入用注射器１は、針先２１から針基端に連通する針穴２４が設けられ針先２１に刃面２２を有する注射針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には針先側端面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、針先側端面３１ｂからの針先２１の突出針長Ｌ１を１．１５ｍｍ±０．１ｍｍとし、注射針２０の軸心に沿った前記刃面２２の刃面長Ｌ２を０．６０ｍｍ±０．１５ｍｍとするというものである。
