The exposure apparatus includes a purge member that includes a humidifier that humidifies supplied gas; a first regulator that regulates a flow rate of first gas which passes through the humidifier; a second regulator that regulates a flow rate of second gas which does not pass through the humidifier; a variable instrument that varies a humidifying performance of the humidifier; a sensor; and a controller. Here, the controller controls the first and the second regulators to adjust a flow rate ratio of the first gas and the second gas on the basis of the humidity of the humidified gas detected by the sensor and a pre-set target humidity, and controls the variable instrument to keep the flow rate of the first gas constant on the basis of an amount of operation of the first regulator and an amount of pre-set target operation.