A tank mounted on a working vehicle is provided with an exterior member including a first plate unit, a second plate unit, a third plate unit, a fourth plate unit, a fifth plate unit, and a sixth plate unit, a first baffle plate joined to a first inner surface of the first plate unit, a second inner surface of the second plate unit, and a third inner surface of the third plate unit, and a second baffle plate joined to a fourth inner surface of the fourth plate unit, a fifth inner surface of the fifth plate unit, and a sixth inner surface of the sixth plate unit.