An exposure apparatus can prevent disadvantages of supplying liquid of reduced cleanliness and formation of watermarks. The exposure apparatus (EX) exposes a substrate (P) by irradiating exposure light (EL) onto the substrate (P) via a projection optical system (PL) and a liquid (LQ), and includes a liquid supply mechanism (10) for supplying the liquid (LQ), and a measuring device (60) which measures a time during which the supply of the liquid from the liquid supply mechanism is stopped (10).