A liquid lens, which forms one optical system together with a solid lens, according to an embodiment, comprises: a first plate in which a cavity for accommodating a conductive liquid and a non-conductive liquid is arranged; a first electrode arranged on the first plate; a second electrode arranged under the first plate; a second plate arranged on the first electrode; and a third plate arranged under the second electrode, wherein a total volume of the conductive liquid and the non-conductive liquid and an area in which the lower surface of the second plate comes in contact with the conductive liquid can be designed so as to meet specific conditions.