A device for retrieving calculus in a lumen of a living body includes an elongated member positionable in the living body lumen and including an inlet, an outlet and a retrieval space between the inlet and the outlet, and a sealing member movably positioned in the lumen of the elongated member to axially move in distal and proximal directions, wherein the sealing member is in sealing contact with the inner surface of the lumen in the elongated member. A plunger is connected to the sealing member and includes two parts separated from one another to form a divided sealing member when the plunger is moved in the distal direction and that directly contact one another to form an integrated sealing member when the plunger is moved in the proximal direction to draw fluid and the calculus into the retrieval space.
