An extrusion molding die (20), for extruding a medical treatment tube (10), in which is formed a flow path (13a), and the like, between dividing wall portions (12), is structured from an outer shape molding die, wherein indented portions (25b,27a, and 28a) are formed, and a pin (22) that is provided with a land portion (23). Additionally, a space that is formed between the outer shape molding die and the pin (22) is structured from a rear portion side molding space portion, which forms the molding material into a cylinder that is pointed at the tip, and a tip side molding space portion, provided with a cross-sectional shape capable of forming the medical treatment tube (10). In addition, in the cross-sectional shape of the tip side molding space portion, the cross-sectional shape at the tip portion is the same as the cross-sectional shape of the medical treatment tube (10), and the cross-sectional shape of the rear side portion is shaped as the portion that shapes the flow path (13a, etc.,) in the land portion (23), with the portions that shape the flow paths (13a and 13c) removed.
