The medical device, in order to deliver the medicine to the patient, includes with the injector assembly (2) and the sealed system. The injector assembly, is connected the medicine reservoir by the barrel (10), and that barrel which it divides forms and the needle cannula (18) of the reservoir (13) and fluid communication state and, includes with the plunger (12) which possesses the thumb pad (15) in order to move the plunger inside stopper (14) and the reservoir which are located inside the reservoir. The sealed system from the 1st position which is arranged from the 1st seal (27) and the needle cannula point which are connected to the front end of the barrel, has with the 2nd seal (22) of mobility to the 2nd position which covers the needle cannula point. To 2nd position, the 2nd seal energization it does the energization component (16) which is controlled by the retention device (32 and 26), on the basis of the movement of stopper to the position where the retention device is released.
