Provided is a pushing device for a drug delivery device that is implanted in the body and coupled to a drug delivery device, which includes a press button for discharging a drug stored inside a housing to the outside, to selectively press the press button, the pushing device including: a body portion detachably coupled to the drug delivery device with skin tissue placed therebetween; and a presser supported to be movable from the body portion in a longitudinal direction thereof and disposed to face the press button.