The insertion device (2) for inserting an intraocular lens (1) into an eye includes a main body (12) including a lens housing portion (12b) in which the lens is housed and a nozzle portion (12c) for ejecting the lens into the eye, a pushing shaft (16) moving the lens from the lens housing portion and pushes out the lens into the eye through a front end opening (12j) of the nozzle portion, a first flow path configured to cause liquid to flow between the front end opening of the nozzle portion and an opening other than the front end opening, and a second flow path configured to cause liquid to flow between a portion (30a) protruding from the front end opening of the nozzle portion and an outside of the insertion device.