To provide a fuel shut-off valve that facilitates fuel flowing into a valve chamber to be easily discharged into a fuel tank.

The fuel shut-off valve 10 blocks fuel in a fuel tank from flowing out to the outside by being closed by the rise of a float 14 when the liquid level of the fuel in the fuel tank rises, and includes communication holes 40 for connecting the inside of the fuel tank and the inside of the valve chamber 38, formed on a bottom wall 34 of a casing 12 forming a valve chamber 38 for housing the float 14 so as to be raised or lowered. The communication hole 40 has a tapered hole shape gradually reduced in diameter toward the undersurface side from the upper surface side of the bottom wall 34.