The invention provides an automatic injection device for providing a subcutaneous injection of a substance into a user, comprising: a housing having an open first end and a second end； a syringe movably disposed in the housing, the syringe including a barrel portion for holding the substance, a hollow needle in fluid communication with the barrel portion for ejecting the substance from the syringe, and a bung for sealing the barrel portion and selectively applying pressure to the substance to force the substance through the hollow needle； a plunger for first moving the syringe towards the first end such that the needle projects from the first end and subsequently applying pressure to the bung, the plunger including a rod connected at a first end to the bung, a compressible expanded central portion and a flange between a second end of the rod and the compressible expanded central portion； and a biasing mechanism for biasing the plunger towards the first open end of the housing, the biasing mechanism disposed about the second end of the rod between the flange and the second end of the housing. The present invention also provides methods and kits for using an automatic injection device, and methods and kits for introducing an automatic injection device comprising a medication based on advantageous properties of the device as compared to a pre-filled syringe. The invention also provides methods and kits for training a recipient on use of the automatic injection device.本發明提供一種用於將一物質皮下注射至一使用者的自動注射裝置，其包含：一個外殼，其具有開放之第一端及第二端；一個注射器，其可移動地安置於該外殼中，該注射器包括一個桶身部分用於承載該物質、一支中空針與該桶身部分形成流體連通以用於自注射器噴射該物質、及一個塞子用於密封該桶身部分及將壓力選擇性地施加至該物質以迫使該物質穿過中空針；一個柱塞，其用於首先將注射器移動朝向第一端使得針自第一端突出且隨後將壓力施加至塞子，該柱塞包括一桿在第一端連接至塞子、一個可壓縮之擴展中心部分、及一凸緣在該桿之第二端與該可壓縮之擴展中心部分之間；及一個偏壓機構，其用於將柱塞偏壓朝向外殼之第一開放端，該偏壓機構安置於凸緣與外殼第二端之間的桿之第二端周圍。本發明亦提供使用一種自動注射裝置之方法及套組，以及用於介紹一種包含藥物之自動注射裝置的方法及套組，其係基於該裝置與一種預填充型注射器相比之有利特性。本發明亦提供用於訓練一接受者使用該自動注射裝置之方法及套組。
