A flush toilet enabling easy cleaning besides capable of preventing dirty water from flowing out is provided. In the flush toilet, a toilet seat is placed on a rim of a toilet body with the toilet seat free to open and close on a pivot axis on a side of a rear end thereof. A projection rib for preventing dirty water from flowing out is formed on a front upper face of the rim so that it protrudes from an outer periphery of the rim. The projection rib is provided so that it is outside a front periphery of the toilet seat when the toilet seat is in closing state.