An endoscope apparatus includes: an insertion section; a flow passage; a closed space forming member configured to form a closed space in at least a portion of an intestine; a pump configured to apply pressurization and depressurization to a liquid in the closed space a plurality of times through the flow passage in a state where the liquid is retained in the closed space; a flow passage allowing the liquid in the closed space to which the pressurization and the depressurization are applied the plurality of times through the flow passage to flow out to an outside of the intestine, and a liquid discharge opening.