To provide a pen-type injector capable of accommodating a relatively large volume of medicine. The present invention comprises a first end (5) comprising a discharge opening that is a carpule (3) having a longitudinal axis (L) and that can be sealed by a sealing part (7), The second end (9) into which at least one plug (13) displaceable in the direction of the longitudinal axis (L) can be inserted, and the sealing part (7) and at least one plug (13) provide tightness resistance A housing (11) having a central axis (M) and containing the carpule (3), and having at least one plug (13) It has a piston rod (34) that cooperates, and a drive part (31) for moving at least one plug (13) within the interior space (15) of the carpule (3). ) Relates to a pen-type injector (1) having a housing (11) that can be fitted into the housing (11) with the second end (9) at the top. The pen-type injector (1) has a piston rod (34) disposed in a fixed position in the housing (11) when viewed in the direction of the central axis (M) of the housing (11), and the drive unit (31 ) Has a drive element (33) cooperating with the carpule (3), and when the drive element (33) activates the drive part (31), the carpule (3) is placed in the housing (11). Moving in the direction of the longitudinal axis (L) of the carpul arranged coaxially with the central axis (M) of the housing (11), and at that time, the piston rod (34) is moved in the longitudinal direction of the housing (11). The piston rod (34), which is held in a fixed position with respect to the second end (9) of the carpule (3), has at least one plug (13) connected to the interior of the carpule (3). It is characterized by moving toward the first end (5) of the carpule in the space (15). [Selection] Figure 1【課題】比較的大きなボリュームの薬剤を収容可能なペン型注入器を得ること。【解決手段】本発明は、長手軸(L)を有するカルプル(3)であって、封止部(7)によって封止可能な放出開口部を備えた第1の端部(5)と、長手軸(L)の方向に変位可能な少なくとも一つの栓(13)を挿入し得る第2の端部(9)と、封止部(7)及び少なくとも一つの栓(13)によって耐密性に閉ざされた内部空間(15)とを有するカルプル(3)、並びに中心軸(M)を有し、カルプル(3)を収容するハウジング(11)で
