There is provided a tank including: a liquid storing chamber; a first wall which expands in a first direction parallel to a horizontal direction and via which a liquid stored in the liquid storing chamber is visible from outside of the liquid storing chamber; a second wall formed with a supply port located above the first wall; a third wall defining a bottom of the liquid storing chamber; and a fourth wall arranged in the liquid storing chamber. A first gap is formed between one of the first and second walls and at least a part of a first end in the first direction, of the fourth wall, located closely to the one of the first and second walls; and a second gap is formed between the third wall and at least a part of a second end in the first direction, of the fourth wall, located closely to the third wall.