Abstract: A spout fitting apparatus being fixed easily to the spout of a container such as a plastic bottle and a bottle such that the cap of an existing container can be employed, as it is, under fixed state without falling into the container, and fluid flows out smoothly from the container at the time of pouring while preventing a hiccoughing phenomenon due to interruption of fluid flow and preventing fluid from scattering to the surroundings of the container, comprising: a locking portion 1 locking to the spout of a container, an falling-prevention stopper 2 provided at the upper edge of the locking portion 1 and preventing the fitting from dropping into the container, a partition wall 3 bonded to the locking portion 1 and separating the fluid outflow path from the inside of the container and an air inflow path from the outside of the container, and an air inflow conduit 4 for extending the opening from the air inflow path side of the partition wall 3 and connecting it to the inside of the container.