PROBLEM TO BE SOLVED: To provide a medical drainage tool preventing deformation such as bending or buckling of a suction instrument caused by the weight of a catheter connected to the upper part of the suction instrument even if the suction instrument is sufficiently flexibly formed to achieve sufficient low pressure of negative pressure of suction.SOLUTION: As the negative pressure is generated in the suction instrument 120 to the upper part of which a connection tube 110 is connected, a drainage fluid is sucked from a wound, etc., in a human body. The suction instrument 120 is formed sufficiently flexible so that the negative pressure in the suction instrument 120 is sufficiently low. However, as the suction instrument 120 is supported at a position further outside than a drainage tube 130 by a support member 140, deformation such as bending or buckling of the flexible suction instrument 120 caused by the weight of the connection tube 110 connected to the upper part can be prevented.
