A dialysis catheter is disclosed which comprises a catheter main body and a closure member. The catheter main body includes a first lumen which communicates with a tip-end hole and a second lumen which communicates with a side hole. The closure member has a shape in which a tip-end side of the closure member is inclined with a reduced diameter for closing off a tip-end opening. The side hole is a long hole extending in the catheter long-axis direction. The major axis of the side hole is at least 1.5 times the outer diameter of the catheter, and the minor axis is between 0.5 and 0.9 times the outer diameter. A base-end side of the closure member extends to the position of the side hole and seals the tip-end region thereof.
