A tank includes: a wall defining a liquid storage chamber, the wall including: an upper wall defining an upper end of the liquid storage chamber, a lower wall defining a lower end of the liquid storage chamber, and an erected wall between the upper wall and the lower wall and through which the liquid inside the liquid storage chamber is visible from outside of the tank; an inlet penetrating through the upper wall or the erected wall; and an outlet, wherein the lower wall includes an upper stage wall making contact with the erected wall; a lower stage wall located at a position separated and away from the erected wall and below the upper stage wall; and a connecting wall connecting the upper and lower stage walls; and the outlet is disposed below the upper stage wall.