A self-injector having a miniaturized drug delivery section is provided. The instrument includes a housing (10) having an internal volume and a drug delivery section (20) having a volume that fits within the housing. The drug delivery section includes a reservoir (30) that contains fluid to be delivered to the user, and a microneedle (22) that is in fluid communication with the reservoir and that can protrude through the housing. The drug delivery section also includes a drive mechanism for pushing fluid out of the reservoir via the microneedle, the volume of the drug delivery section being less than 40% of the internal volume of the housing. The volume of the medicine delivery part may be less than 30% of the inner volume of the housing.小型化した薬剤送出部を持つ自己注射器が提供される。この器具は、内容積を有するハウジング(１０)と、このハウジング内に収まる容積を持った薬剤送出部(２０)とを含む。薬剤送出部は、使用者に送出される流体を収容するリザーバー(３０)と、このリザーバーと流体連通すると共にハウジングを通って突出可能な微小針(２２)とを含む。薬剤送出部はまた、微小針を介してリザーバーから流体を押し出すための駆動機構をも含み、この薬剤送出部の容積はハウジングの内容積の４０％よりも少ない。薬剤送出部の容積がハウジングの内容積の３０％よりも少ない場合がある。
