The present invention discloses a method for manufacturing a catheter, including the following steps: supplying a molten resin material to the surroundings of a core wire (90) to form a hollow pipe (82) which has the core wire (90) inserted therein； disposing the hollow pipe (82), in which the core wire (90) has been inserted, on the outer peripheral side of the main cavity forming region of a resin tube-shaped body section (10)； stretching the core wire (90) located within the hollow pipe (82) to reduce the diameter of the core wire (90), and separating the hollow pipe (82) and the core wire (90) from each other, and then extracting the core wire (90) from the hollow pipe (82) to form a sub-cavity； and inserting an operating wire into the hollow pipe (82).本發明之導液管之製造方法包括如下步驟：向芯線(90)之周圍供給熔融狀態之樹脂材料，將內部插入有芯線(90)之中空管(82)成形；於樹脂製之管狀主體部(10)之主腔形成區域的外周側，配置內部插入有上述芯線(90)之中空管(82)；使中空管(82)內部之上述芯線(90)伸展而縮小直徑，將中空管(82)與上述芯線(90)剝離後，自中空管(82)內部拔出上述芯線(90)，而形成子腔；以及將操作線插入至中空管(82)內部。
