In an exposure device 100 having a vertically movable stage device 120, and which performs exposure by projecting a pattern recorded on a hologram mask 130 onto a substrate to be exposed 110 on which is formed a photosensitive material film 112 and which is placed on the above stage device, a film thickness measurement mechanism 160, 162 measures the thickness of the photosensitive material film 112, and based on the measured film thickness a light amount control mechanism 162 controls the amount of exposure light from the exposure light source 140. An appopriate amount of light is set according to the film thickness, so that an accurate pattern can be formed in a single exposure pass.