There is provided a liquid-to-gas contact device comprising: a liquid-to-gas contact medium which is a honeycomb structural body formed of a porous material including a plurality of through channels defined by a plurality of partition walls and extending through the structural body in an axial direction, and including a plurality of flow passages extending through the honeycomb structural body from an outer peripheral surface side and formed isolatedly from the through channels; and a container which includes a gas inlet, a gas outlet, a liquid supply port, a storage tank for liquid, and, if desired, a liquid discharge port and in which the liquid-to-gas contact medium is to be stored. A capillarity phenomenon function possessed by the liquid-to-gas contact medium is used to provide the device which has a superior thermal efficiency and which can be constituted to be simple and compact.