A container separates a needle unit from a pen syringe and houses the needle unit. An insertion opening that receives a needle unit has an inner diameter slightly smaller than the outer diameter of the needle unit. When a user inserts the needle unit of a used pen syringe into the insertion opening and rotates the syringe against the needle unit fixed by the linear protrusions inside the insertion opening engaging with the linear protrusions around the needle unit in the rotational direction, the syringe is unscrewed from the needle unit. When the closer is closed while the separated needle unit remains in the insertion opening, a pusher provided on the lower surface of the closer pushes the needle unit downward and drops the needle unit into the container body.
