FUEL TANK CAP OF A STRADDLED VEHICLE

A cap (36) comprises a connecting portion (411) attached to a support (34) via a hinge (35). An operating member (37) is attached to the cap (36) and operable by a rider or person. A packing (38) is attached to a bottom surface of the cap (36). The packing (38) seals between the cap (36) and a fuel filler port (33) when the cap (36) is located in a closed position. A water guide (39) extends from the packing (38) towards the connecting portion (411). The water guide (39) has a band shape, and is arranged between the connecting portion (411) and the fuel filler port (33) when the cap (36) is located in an open position. An upper surface of the cap (36) is exposed to an outside of a vehicle (1). The upper surface of the cap (36) comprises a recess (361) extending towards the connecting portion (411). The operating member (37) is arranged in the recess (361).