A humidifier may include a water tank that stores water, a heating device configured to be supplied with water from the water tank and heat the water, a humidifying device that is connected with the heating device and produces humidified air using water supplied from the heating device, a first connection tube that connects the heating device and the humidifying device, a second connection tube that connects the heating device and the humidifying device at a position different from the first connection tube, and a pump disposed at a side of the second connection tube that pumps water stored in the humidifying device to the heating device.