Drug delivery device

The utility model provides a drug delivery device which comprises a first tube body, a second tube body and a third tube body, a containing space is arranged in the first tube body, a detachable portion is arranged at the injection end of the first tube body, liquid drug and a stop assembly are arranged in the containing space, a necking portion is arranged at the end, away from the detachable portion, of the first tube body, and at least one integrated surrounding portion of the stop assembly is larger than the necking portion. The second tube body comprises a tube sealing part, a pressing part and a communicating tube part which are connected with one another, the pressing part is used for extruding out liquid medicine, the tail end of the tube sealing part forms a closed end, the end, away from the tube sealing part, of the communicating tube part is communicated with the necking part, and the pressing part is communicated between the tube sealing part and the communicating tube part; the accommodating spa