To provide a humidifier, convenient in using without necessitating the setting of a cutting timer at every times of going bed and eliminating the provision of uncomfortable feeling due to dried air in a room upon getting up.

A humidifier 1 is provided with a vessel main body 2, an internal vessel 8 arranged in the vessel main body 2, heating means (water boiling heater 9, humidifying heater 10) for heating water contained in the internal vessel 8, a lid 12, attached to the vessel main body 2 for opening and closing the upper opening of the internal vessel 8, and a control means 3 for controlling the heating means to effect humidifying operation. Such a humidifier is provided with a light sensor (detecting unit) for detecting the brightness in a neighborhood and when the amount of light lower than a reference value is detected by the light sensor during a predetermined continued period to time, humidifying operation is stopped and, on the contrary, when the amount of light higher than a reference value is detected by the light sensor, the humidifying operation is started.