PURPOSE: To provide a fuel filling port capable of securing a discharge quantity and discharging the overflowing fuel in a short time when the fuel overflows due to a failure of the automatic stop operation of a fuel filling gun.

CONSTITUTION: A moving retainer 7, a protective tube body 5, a cylindrical holding ring 11 and an outer periphery seal member 14 are arranged in a fuel filling port main body 1. The moving retainer 7 has a circular seal member 10 capable of sealing the outer periphery of a fuel filling gun G. The holding ring 11 holds a holding member 16. The holding member 16 holds the moving retainer 7 via a spring 15. The holding member 16 has a moving member 18 moving the moving retainer 7 to bring the circular seal member 10 into contact with the outer periphery of the fuel filling gun G when the fuel filling gun G is inserted. Recesses 22a, 31a for expanding a gap H with the moving retainer 7 are formed on the inner periphery of the holding ring 11.