The present invention relates to an air conditioner and a control method thereof. The air conditioner comprises: a body for discharging heat-exchanged air; a water tank disposed toward the front and exposed to the outside when a front panel is opened; and a humidification module for generating humidified air by converting water supplied from the water tank to a steam tank into fine particles. The humidification module, when setting of a humidity mode, performs initial humidification by performing preheating for a predetermined period when the steam tank reaches a set water level, and performs set humidification to supply water after draining the water from the steam tank before humidifying, thereby easily adjusting the amount of water injected into the steam tank even without attaching a separate sensor to the inside of the steam tank. The water supplied from the water tank to the steam tank is adjusted during an initial operation of the humidification module to reduce the total amount of heated water, thereby enabling the humidification module to provide steam humidification in a short time.