Abstract: A breather pipe with a leakage checking device for a container which allows air in the container to be ventilated when the mobile container transports high viscosity liquid such as engine fuel of automobiles normally, and on the other hand closes up the breather pipe to prevent a leakage of the liquid when the moving container is accelerated, decelerated or turned rapidly, or inclined or overturned. The breather pipe comprises a pipe member having a lower part which is vertically mounted on an opening formed at an upper surface of the container and an upper part which is curved downwardly. The pipe member also has an upper throat and regularly circumferentially spaced lower depressions formed at the circumferential surface thereof, and a spherical float positioned in the pipe member between the upper throat and the lower depressions.