This drug delivery device delivers a drug between a syringe barrel and a drug container, and, by enveloping the entire the drug container used in drug delivery, prevents exposure to hazardous drugs adhering to the drug container. This drug delivery device includes: a first member connected to the drug container on the side of a stopper a second member connected to the first member and to the syringe barrel and a third member connected to the first member and covering the drug container in a sealed state. The first member has a first hollow needle member and a drug container holder, and the second member has a second hollow needle member. The third member has an opening portion, a bottom surface portion where the drug container is stably mounted, and a flexible member which is connected to the opening portion and the bottom surface portion.
