A sterilization and humidification apparatus includes a heating chamber, a filter and a humidification chamber. The heating chamber heats a gas so as to sterilize the gas. The humidification chamber is adapted so that a liquid, which has been filtered by the filter, evaporates into the sterilized gas, thereby causing the sterilized gas to cool, and outputting a humidified gas at a desired temperature. The apparatus may include a bypass chamber to provide a path for the gas to bypass the humidification chamber. The apparatus may be adapted particularly for use in an incubator.