A degassing apparatus includes a hollow fiber disposed on a supply path for a liquid, the hollow fiber including a gas permeable film permeable to dissolved gas in the liquid. The liquid is refluxed and brought into contact with a hollow interior or exterior of the hollow fiber, and a side of the hollow fiber not in contact with the liquid is depressurized to allow the dissolved gas in the liquid to permeate the depressurized side. The degassing apparatus further includes a clogging detector that detects clogging of the hollow interior of the hollow fiber caused by a component in the liquid.