A liquid supplying system includes a tank, a first tubular portion, a second tubular portion, a sleeve portion, and a liquid bottle. The first and second tubular portions have inner ends positioned inside a storage chamber of the tank, and outer ends positioned outside of the storage chamber. The first and second tubular portions are positioned inside the sleeve portion. The sleeve portion includes a first screw portion and a first engagement portion. The liquid bottle includes an outer sleeve connectable to the sleeve portion. The sleeve portion includes a second screw portion threadingly engageable with the first screw portion, and a second engagement portion engageable with the first engagement portion. The first engagement portion can guide the second engagement portion to move in a direction parallel to a center axis of the sleeve portion during connection of the outer sleeve to the sleeve portion.