A mixed injection port capable of suppressing the continuous accumulation of medical fluid or blood therein and allowing efficient internal cleaning, wherein a recirculation part (140) is formed at a step between an inner cavity (114) and a thin tube part (117). Even if the fluid is accumulated in a clearance area (1141) produced in the inner cavity (114) when a lure is inserted into a slit (131), the fluid can be securely replaced with the fluid newly flowing therein through a septum (130) and the continuous accumulation of the fluid can be suppressed. A more efficient internal cleaning can be realized by installing a fluid accumulation prevention part such as an annular rib between the septum (130) and the inside wall of the inner cavity (114) and burying the clearance area (1141).