A medical blocking tool includes a core section and a swelling section which is provided around the core section. The core section has a function of a reinforcing member reinforcing the swelling section. The core section is formed as a bar-shaped wire rod and is formed in a linear shape. The swelling section is formed of a swelling material which is swelled (expanded) by absorbing a liquid thereinto so that the volume thereof is increased. The swelling section is adapted to be swelled until a bronchial tube is blocked while coming into close contact with the inner wall of the bronchial tube at a portion to be blocked (a blocking target portion) in the bronchial tube. The swelling section is formed along the wire rod of the core section 2, and is formed in a bar shape while coating the entire part of the wire rod (core section). The medical blocking tool is formed in a cylindrical shape.