Disclosed are an apparatus for and a method of manufacturing a semiconductor device. The apparatus includes a chamber, an evaporator that evaporates an organic source to provide a source gas on a substrate in the chamber, a vacuum pump that pumps the source gas and air from the chamber, an exhaust line between the vacuum pump and the chamber, and an analyzer connected to the exhaust line. The analyzer detects a derived molecule produced from the organic source and determines a replacement time of the evaporator.