PURPOSE: To improve the absorbability of the absorbent layer, by setting the thickness of respective parts of the absorbent layer held in the absorbing and dehydrating column correspondingly to the velocity of gas flowing into the said parts, in a water making apparatus which obtains water from the moisture of gas.

CONSTITUTION: In the absorption process, the moisture of the atmospheric air is absorbed by the absorbent layer held in the absorbing and dehydrating column; next, in the dehydration process, heat is given to the absorbent layer in order to release the absorbed moisture as steam; further, the high-temprature and high- humidity air passed through the absorbing and dehydrating column is cooled to condense the moisture, and the water in liquid state is obtained. The thickness of the absorbent layer 1a is enlarged at the middle part wherein the velocity of the in-flowing air is large; hereby, the air velocity flowing into respective parts of the absorbent layer 1a is made proportinal to the thickness of corresponding part. As a result, the absorbability of the absorbent layer 1a is fully displayed.