A multi lumen catheter including an inner tube having a front tip, an outer tube, a tube or lumen for inserting a guide wire, a blood extraction lumen and a blood return lumen which are formed in the outer tube and inner tube, respectively, or both in the outer tube, wherein the inner tube is inserted in the outer tube, and allowed to slide relative thereto, and the front tip is jointed to the front end of the outer tube to shut off communication of the lumens with the exterior. A multi-lumen catheter with balloon includes a balloon provided on a tabular body at a front end thereof, a blood return port and a blood extraction port provided in the tubular body on opposite sides of the balloon, and an outer cylinder slidable on the tubular body to close the blood extraction and blood return ports and the balloon.