A drainage structure has: a bathtub (first wet area fixture) at which waste water becomes collect-and-flow waste water that is drained after having been collected; a wash place (second wet area fixture) at which waste water becomes continuous waste water that is not collected; a first drainage trap that is provided at a drain of the bathtub; a second drainage trap that is provided at the wash place; a first bypass pipe that connects a drainage pipe (downstream side region) of the first drainage trap and a drainage pipe (downstream side region) of the second drainage trap, at least a portion of the first bypass pipe being positioned higher than both the first drainage trap and the second drainage trap; a first siphoning drainage pipe that is connected to a downstream side of the first drainage trap and to a downstream side of the first bypass pipe; and a second siphoning drainage pipe that is connected to a downstream side of the second drainage trap and to a downstream side of the first bypass pipe.