PURPOSE: To eliminate the use of such parts as a water reservoir pan and a water level sensor, while retaining water supplying performance to water absorbing elements in a humidifier of natural vaporization, in which each element of a group of water absorbing elements arranged side by side horizontally is made absorb water supplied through a water supply pipe having an opening and closing valve.

CONSTITUTION: A water supplying pipe 4 is arranged horizontally above a group of elements 2 to cross each element 1 of the group of elements 2, and a water supplying part 4a to supply water to the group of elements 2 is provided in the water supplying pipe 4.