To provide a fuel shutoff valve 10 preventing leakage of fuel to the outside even if the vicinity of an opening of a connection passage 31b is submerged in liquid due to tilting of a fuel tank FT.

The fuel shutoff valve 10 comprises a casing 20 having a casing body defining a valve chamber 30S and a partition plate 37, and a float mechanism 50 having a valve part 52. The connection passage 31b is opened and closed by the valve part 52 with vertical movement of the float mechanism 50. The partition plate 37 is horizontally arranged above an air vent 32a in the casing body 30 and divides the valve chamber 30S into a lower valve chamber 30Sa and an upper valve chamber 30Sb. The partition plate 37 is formed of a through-hole 38a. A gap between the through-hole 38 and the valve part 52 forms a passage 30Sc connected to the connection passage 31b via the lower valve chamber 30Sa and the upper valve chamber 30Sb.